From 470d6a1c0fd4333280fe6bd75264f6f88670ef11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Wed, 7 Dec 2022 12:21:57 +0100
Subject: [PATCH 01/15] Upgrade GitHub actions from v2 to v3

---
 .github/workflows/node.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/node.yml b/.github/workflows/node.yml
index 97e316e..aeb694c 100644
--- a/.github/workflows/node.yml
+++ b/.github/workflows/node.yml
@@ -15,9 +15,9 @@ jobs:
         node: ['18', '17', '16', '15', '14']
     container: node:${{ matrix.node }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Restore dependencies cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
         path: ~/.npm
         key: ${{ runner.os }}-${{ matrix.node }}-${{ hashFiles('**/package-lock.json') }}

From 67dcf36f6a690a79b80d43a04634efcb2695044e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Wed, 7 Dec 2022 12:24:57 +0100
Subject: [PATCH 02/15] Add Node.js version 19 to GitHub testing action

---
 .github/workflows/node.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/node.yml b/.github/workflows/node.yml
index aeb694c..06f64f4 100644
--- a/.github/workflows/node.yml
+++ b/.github/workflows/node.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: ['18', '17', '16', '15', '14']
+        node: ['19', '18', '17', '16', '15', '14']
     container: node:${{ matrix.node }}
     steps:
     - uses: actions/checkout@v3

From 041e3d15b43532d0bf1a4f16357f08371d3b5ef5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Wed, 7 Dec 2022 16:29:08 +0100
Subject: [PATCH 03/15] Add Sequence class

---
 src/index.js          |  4 +++-
 src/sequence.js       | 19 +++++++++++++++++++
 test/sequence.test.js | 38 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 src/sequence.js
 create mode 100644 test/sequence.test.js

diff --git a/src/index.js b/src/index.js
index 60164c2..2946751 100644
--- a/src/index.js
+++ b/src/index.js
@@ -2,9 +2,11 @@ import Url from './url'
 import Source from './source'
 import Color from './color'
 import Position from './position'
+import Sequence from './sequence'
 
 const url = Url.url
 const color = Color.color
 const position = Position.position
+const sequence = Sequence.sequence
 
-export default { url, Source, color, position }
+export default { url, Source, color, position, sequence }
diff --git a/src/sequence.js b/src/sequence.js
new file mode 100644
index 0000000..6d2e665
--- /dev/null
+++ b/src/sequence.js
@@ -0,0 +1,19 @@
+export default class Sequence {
+  static #DEFAULT_SIZE = 16
+
+  static sequence(first, last, size = Sequence.#DEFAULT_SIZE) {
+    if (size <= 0) return []
+    if (size === 1) return [first]
+    if (size === 2) return [first, last]
+
+    const ratio = (last / first) ** (1 / (size - 1))
+
+    const sequence = [first]
+    for (let i = 1; i < size - 1; i++) {
+      sequence.push(sequence[i - 1] * ratio)
+    }
+    sequence.push(last)
+
+    return sequence.map((value) => Math.round(value))
+  }
+}
diff --git a/test/sequence.test.js b/test/sequence.test.js
new file mode 100644
index 0000000..2715152
--- /dev/null
+++ b/test/sequence.test.js
@@ -0,0 +1,38 @@
+import Sequence from '../src/sequence'
+
+describe('Sequence', () => {
+  describe('sequence', () => {
+    it('returns an array with sequence default size', () => {
+      expect(Sequence.sequence(100, 8192)).toEqual([100, 134, 180, 241, 324, 434, 583, 781, 1048, 1406, 1886, 2530, 3394, 4553, 6107, 8192])
+      expect(Sequence.sequence(8192, 100)).toEqual([8192, 6107, 4553, 3394, 2530, 1886, 1406, 1048, 781, 583, 434, 324, 241, 180, 134, 100])
+    })
+
+    it('returns an empty array when the size of the sequence is a negative number', () => {
+      expect(Sequence.sequence(100, 8192, -1)).toEqual([])
+      expect(Sequence.sequence(8192, 100, -1)).toEqual([])
+    })
+
+    it('returns an empty array when the size of the sequence is zero', () => {
+      expect(Sequence.sequence(100, 8192, 0)).toEqual([])
+      expect(Sequence.sequence(8192, 100, 0)).toEqual([])
+    })
+
+    it('returns an array with expected ascending order sequence', () => {
+      expect(Sequence.sequence(100, 8192, 1)).toEqual([100])
+      expect(Sequence.sequence(100, 8192, 2)).toEqual([100, 8192])
+      expect(Sequence.sequence(100, 8192, 3)).toEqual([100, 905, 8192])
+      expect(Sequence.sequence(100, 8192, 4)).toEqual([100, 434, 1886, 8192])
+      expect(Sequence.sequence(100, 8192, 16)).toEqual([100, 134, 180, 241, 324, 434, 583, 781, 1048, 1406, 1886, 2530, 3394, 4553, 6107, 8192])
+      expect(Sequence.sequence(100, 8192, 32)).toEqual([100, 115, 133, 153, 177, 204, 235, 270, 312, 359, 414, 477, 550, 634, 731, 843, 972, 1120, 1291, 1488, 1716, 1978, 2280, 2628, 3029, 3492, 4025, 4640, 5348, 6165, 7107, 8192])
+    })
+
+    it('returns an array with expected descending order sequence', () => {
+      expect(Sequence.sequence(8192, 100, 1)).toEqual([8192])
+      expect(Sequence.sequence(8192, 100, 2)).toEqual([8192, 100])
+      expect(Sequence.sequence(8192, 100, 3)).toEqual([8192, 905, 100])
+      expect(Sequence.sequence(8192, 100, 4)).toEqual([8192, 1886, 434, 100])
+      expect(Sequence.sequence(8192, 100, 16)).toEqual([8192, 6107, 4553, 3394, 2530, 1886, 1406, 1048, 781, 583, 434, 324, 241, 180, 134, 100])
+      expect(Sequence.sequence(8192, 100, 32)).toEqual([8192, 7107, 6165, 5348, 4640, 4025, 3492, 3029, 2628, 2280, 1978, 1716, 1488, 1291, 1120, 972, 843, 731, 634, 550, 477, 414, 359, 312, 270, 235, 204, 177, 153, 133, 115, 100])
+    })
+  })
+})

From 9f79f81f84431128fb85eeecaf249fe70fdfc8d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Wed, 28 Dec 2022 14:12:24 +0100
Subject: [PATCH 04/15] Normalize url params with null value

---
 src/utils.js     |  2 ++
 test/url.test.js | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/src/utils.js b/src/utils.js
index 11a2718..71ce87b 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -33,6 +33,8 @@ export default class Utils {
     switch(true) {
       case key === 'expires' && value instanceof Date:
         return { [key]: Math.floor(value / 1000) }
+      case value === null:
+        return { [key]: '' }
       default:
         return { [key]: value }
     }
diff --git a/test/url.test.js b/test/url.test.js
index dc40c9e..2c7b411 100644
--- a/test/url.test.js
+++ b/test/url.test.js
@@ -23,6 +23,12 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png')
     })
 
+    it('returns url with null params', () => {
+      const url = Url.url('assets', 'example.jpeg', { width: 200, download: null })
+
+      expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
+    })
+
     it('returns url with params using string path', () => {
       const url = Url.url('assets', 'example.jpeg', { width: 200, height: 300, watermark: 'example.svg', format: 'png' })
 
@@ -225,6 +231,12 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png')
     })
 
+    it('returns url with null params', () => {
+      const url = Url.url(new Source('assets'), 'example.jpeg', { width: 200, download: null })
+
+      expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
+    })
+
     it('returns url with params using string path', () => {
       const url = Url.url(
         new Source('assets'),
@@ -573,6 +585,19 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png&signature=VJ159IlBl_AlN59QWvyJov5SlQXlrZNpXgDJLJgzP8g')
     })
 
+    it('returns url with null params', () => {
+      const url = Url.url(
+        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
+        'example.jpeg',
+        {
+          width: 200,
+          download: null
+        }
+      )
+
+      expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=&signature=ljL9HNRaxVrk7jfQaf6FPYFZn4RJzQPCW-aVNJoIQI8')
+    })
+
     it('returns url with params using string path', () => {
       const url = Url.url(
         new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),

From 6d69c69a4b5106ed483cb1785ddf9bcf773f39d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Fri, 30 Dec 2022 11:30:56 +0100
Subject: [PATCH 05/15] Rename internal constant

---
 src/sequence.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/sequence.js b/src/sequence.js
index 6d2e665..8d4d44d 100644
--- a/src/sequence.js
+++ b/src/sequence.js
@@ -8,12 +8,12 @@ export default class Sequence {
 
     const ratio = (last / first) ** (1 / (size - 1))
 
-    const sequence = [first]
+    const seq = [first]
     for (let i = 1; i < size - 1; i++) {
-      sequence.push(sequence[i - 1] * ratio)
+      seq.push(seq[i - 1] * ratio)
     }
-    sequence.push(last)
+    seq.push(last)
 
-    return sequence.map((value) => Math.round(value))
+    return seq.map((value) => Math.round(value))
   }
 }

From aea75368630c4e264225e0ff991fc13b8014070f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Sat, 31 Dec 2022 16:22:31 +0100
Subject: [PATCH 06/15] Improve url tests

---
 README.md        |   2 +-
 src/url.js       |  10 +-
 test/url.test.js | 354 +++++++----------------------------------------
 3 files changed, 58 insertions(+), 308 deletions(-)

diff --git a/README.md b/README.md
index 12e5d4b..c8822e4 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,7 @@ Imglab.url('assets', 'example.jpeg', { width: 500, height: 600 })
 
 You can use `Imglab.url` function to generate imglab compatible URLs for your application.
 
-The easiest way to generate a URL is to specify the `sourceName`, `path` and required `parameters`:
+The easiest way to generate a URL is to specify the name of the `source`, a `path` and required `parameters`:
 
 ```javascript
 Imglab.url('assets', 'image.jpeg', { width: 500, height: 600 })
diff --git a/src/url.js b/src/url.js
index 5903961..685f613 100644
--- a/src/url.js
+++ b/src/url.js
@@ -3,13 +3,13 @@ import Signature from './signature'
 import Utils from './utils'
 
 export default class Url {
-  static url(sourceNameOrSource, path, params = {}) {
-    if (typeof sourceNameOrSource === 'string') {
-      return Url.#urlForSource(new Source(sourceNameOrSource), path, params)
+  static url(source, path, params = {}) {
+    if (typeof source === 'string') {
+      return Url.#urlForSource(new Source(source), path, params)
     }
 
-    if (sourceNameOrSource instanceof Source) {
-      return Url.#urlForSource(sourceNameOrSource, path, params)
+    if (source instanceof Source) {
+      return Url.#urlForSource(source, path, params)
     }
 
     throw new Error('Invalid source name or source')
diff --git a/test/url.test.js b/test/url.test.js
index 2c7b411..030ebd6 100644
--- a/test/url.test.js
+++ b/test/url.test.js
@@ -9,6 +9,9 @@ const position = Position.position
 const SECURE_KEY = 'ixUd9is/LDGBw6NPfLCGLjO/WraJlHdytC1+xiIFj22mXAWs/6R6ws4gxSXbDcUHMHv0G+oiTgyfMVsRS2b3'
 const SECURE_SALT = 'c9G9eYKCeWen7vkEyV1cnr4MZkfLI/yo6j72JItzKHjMGDNZKqPFzRtup//qiT51HKGJrAha6Gv2huSFLwJr'
 
+const SOURCE = new Source('assets')
+const SECURE_SOURCE = new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT })
+
 describe('Url', () => {
   describe('url using source name', () => {
     it('returns url without params', () => {
@@ -88,8 +91,6 @@ describe('Url', () => {
     })
 
     it('returns url with params using url function with source', () => {
-      const source = new Source('assets')
-
       const url =
         Url.url(
           'assets',
@@ -97,7 +98,7 @@ describe('Url', () => {
           {
             width: 200,
             height: 300,
-            watermark: Url.url(source, 'example.svg', { width: 100, format: 'png' }),
+            watermark: Url.url(SOURCE, 'example.svg', { width: 100, format: 'png' }),
             format: 'png'
           }
         )
@@ -220,26 +221,26 @@ describe('Url', () => {
 
   describe('url using source', () => {
     it('returns url without params', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg')
+      const url = Url.url(SOURCE, 'example.jpeg')
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg')
     })
 
     it('returns url with params', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg', { width: 200, height: 300, format: 'png' })
+      const url = Url.url(SOURCE, 'example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with null params', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg', { width: 200, download: null })
+      const url = Url.url(SOURCE, 'example.jpeg', { width: 200, download: null })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
     })
 
     it('returns url with params using string path', () => {
       const url = Url.url(
-        new Source('assets'),
+        SOURCE,
         'example.jpeg',
         {
           width: 200,
@@ -254,7 +255,7 @@ describe('Url', () => {
 
     it('returns url with params using string path with inline params', () => {
       const url = Url.url(
-        new Source('assets'),
+        SOURCE,
         'example.jpeg',
         {
           width: 200,
@@ -268,15 +269,13 @@ describe('Url', () => {
     })
 
     it('returns url with params using url with source', () => {
-      const source = new Source('assets')
-
       const url = Url.url(
-        source,
+        SOURCE,
         'example.jpeg',
         {
           width: 200,
           height: 300,
-          watermark: Url.url(source, 'example.svg', { width: 100, format: 'png' }),
+          watermark: Url.url(SOURCE, 'example.svg', { width: 100, format: 'png' }),
           format: 'png'
         }
       )
@@ -286,7 +285,7 @@ describe('Url', () => {
 
     it('returns url with params using url with source name', () => {
       const url = Url.url(
-        new Source('assets'),
+        SOURCE,
         'example.jpeg',
         {
           width: 200,
@@ -300,25 +299,25 @@ describe('Url', () => {
     })
 
     it('returns url with params using underscore attributes', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg', { trim: 'color', trim_color: 'orange' })
+      const url = Url.url(SOURCE, 'example.jpeg', { trim: 'color', trim_color: 'orange' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?trim=color&trim-color=orange')
     })
 
     it('returns url with params using camel case attributes', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg', { trim: 'color', trimColor: 'orange' })
+      const url = Url.url(SOURCE, 'example.jpeg', { trim: 'color', trimColor: 'orange' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?trim=color&trim-color=orange')
     })
 
     it('returns url with params using quoted attributes with hyphens', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg', { trim: 'color', 'trim-color': 'orange' })
+      const url = Url.url(SOURCE, 'example.jpeg', { trim: 'color', 'trim-color': 'orange' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?trim=color&trim-color=orange')
     })
 
     it('returns url with expires param using a Date instance', () => {
-      const url = Url.url(new Source('assets'), 'example.jpeg', { width: 200, height: 300, expires: new Date(1464096368 * 1000) })
+      const url = Url.url(SOURCE, 'example.jpeg', { width: 200, height: 300, expires: new Date(1464096368 * 1000) })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&expires=1464096368')
     })
@@ -394,168 +393,73 @@ describe('Url', () => {
     })
 
     it('returns url with path starting with slash', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path starting with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/example image%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/example image%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path starting and ending with slash', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/example.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/example.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path starting and ending with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/example image%2C01%2C02.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/example image%2C01%2C02.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with subfolder path starting with slash', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder/example.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with subfolder path starting with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/subfolder images/example image%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/subfolder images/example image%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder%20images/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with subfolder path starting and ending with slash', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/subfolder/example.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, '/subfolder/example.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder/example.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with subfolder path starting and ending with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets'),
-        '/subfolder images/example image%2C01%2C02.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        })
+      const url = Url.url(SOURCE, '/subfolder images/example image%2C01%2C02.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder%20images/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path using a http url', () => {
-      const url = Url.url(
-        new Source('assets'),
-        'http://assets.com/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, 'http://assets.com/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/http%3A%2F%2Fassets.com%2Fsubfolder%2Fexample.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path using a http url with reserved characters', () => {
-      const url = Url.url(
-        new Source('assets'),
-        'http://assets.com/subfolder/example%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, 'http://assets.com/subfolder/example%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/http%3A%2F%2Fassets.com%2Fsubfolder%2Fexample%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path using a https url', () => {
-      const url = Url.url(
-        new Source('assets'),
-        'https://assets.com/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, 'https://assets.com/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/https%3A%2F%2Fassets.com%2Fsubfolder%2Fexample.jpeg?width=200&height=300&format=png')
     })
 
     it('returns url with path using a https url with reserved characters', () => {
-      const url = Url.url(
-        new Source('assets'),
-        'https://assets.com/subfolder/example%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SOURCE, 'https://assets.com/subfolder/example%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/https%3A%2F%2Fassets.com%2Fsubfolder%2Fexample%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
@@ -563,59 +467,32 @@ describe('Url', () => {
 
   describe('url using secure source', () => {
     it('returns url without params', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg'
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg')
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?signature=aRgmnJ-7b2A0QLxXpR3cqrHVYmCfpRCOglL-nsp7SdQ')
     })
 
     it('returns url with params', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png&signature=VJ159IlBl_AlN59QWvyJov5SlQXlrZNpXgDJLJgzP8g')
     })
 
     it('returns url with null params', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          width: 200,
-          download: null
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { width: 200, download: null })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=&signature=ljL9HNRaxVrk7jfQaf6FPYFZn4RJzQPCW-aVNJoIQI8')
     })
 
     it('returns url with params using string path', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          watermark: 'example.svg',
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, watermark: 'example.svg', format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&watermark=example.svg&format=png&signature=xrwElVGVPyOrcTCNFnZiAa-tzkUp1ISrjnvEShSVsAg')
     })
 
     it('returns url with params using string path with inline params', () => {
       const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
+        SECURE_SOURCE,
         'example.jpeg',
         {
           width: 200,
@@ -629,15 +506,13 @@ describe('Url', () => {
     })
 
     it('returns url with params using url with source', () => {
-      const source = new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT })
-
       const url = Url.url(
-        source,
+        SECURE_SOURCE,
         'example.jpeg',
         {
           width: 200,
           height: 300,
-          watermark: Url.url(source, 'example.svg', { width: 100, format: 'png' }),
+          watermark: Url.url(SECURE_SOURCE, 'example.svg', { width: 100, format: 'png' }),
           format: 'png'
         }
       )
@@ -647,7 +522,7 @@ describe('Url', () => {
 
     it('returns url with params using url with source name', () => {
       const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
+        SECURE_SOURCE,
         'example.jpeg',
         {
           width: 200,
@@ -661,54 +536,25 @@ describe('Url', () => {
     })
 
     it('returns url with params using underscore attributes', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          trim: 'color',
-          trim_color: 'orange'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { trim: 'color', trim_color: 'orange' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?trim=color&trim-color=orange&signature=cfYzBKvaWJhg_4ArtL5IafGYU6FEgRb_5ZADIgvviWw')
     })
 
     it('returns url with params using camel case attributes', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          trim: 'color',
-          trimColor: 'orange'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { trim: 'color', trimColor: 'orange' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?trim=color&trim-color=orange&signature=cfYzBKvaWJhg_4ArtL5IafGYU6FEgRb_5ZADIgvviWw')
     })
 
     it('returns url with params using quoted attributes with hyphens', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          trim: 'color',
-          'trim-color': 'orange'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { trim: 'color', 'trim-color': 'orange' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?trim=color&trim-color=orange&signature=cfYzBKvaWJhg_4ArtL5IafGYU6FEgRb_5ZADIgvviWw')
     })
 
     it('returns url with expires param using a Date instance', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          expires: new Date(1464096368 * 1000)
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, expires: new Date(1464096368 * 1000) })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&expires=1464096368&signature=DpkRMiecDlOaQAQM5IQ8Cd4ek8nGvfPxV6XmCN0GbAU')
     })
@@ -788,169 +634,73 @@ describe('Url', () => {
     })
 
     it('returns url with path starting with slash', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png&signature=VJ159IlBl_AlN59QWvyJov5SlQXlrZNpXgDJLJgzP8g')
     })
 
     it('returns url with path starting with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/example image%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/example image%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png&signature=yZcUhTCB9VB3qzjyIJCCX_pfJ76Gb6kHe7KwusAPl-w')
     })
 
     it('returns url with path starting and ending with slash', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/example.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/example.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&format=png&signature=VJ159IlBl_AlN59QWvyJov5SlQXlrZNpXgDJLJgzP8g')
     })
 
     it('returns url with path starting and ending with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/example image%2C01%2C02.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/example image%2C01%2C02.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png&signature=yZcUhTCB9VB3qzjyIJCCX_pfJ76Gb6kHe7KwusAPl-w')
     })
 
     it('returns url with subfolder path starting with slash', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder/example.jpeg?width=200&height=300&format=png&signature=3jydAIXhF8Nn_LXKhog2flf7FsACzISi_sXCKmASkOs')
     })
 
     it('returns url with subfolder path starting with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/subfolder images/example image%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/subfolder images/example image%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder%20images/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png&signature=2oAmYelI7UEnvqSSPCfUA25TmS7na1FRVTaxfe5ADyY')
     })
 
     it('returns url with subfolder path starting and ending with slash', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder/example.jpeg?width=200&height=300&format=png&signature=3jydAIXhF8Nn_LXKhog2flf7FsACzISi_sXCKmASkOs')
     })
 
     it('returns url with subfolder path starting and ending with slash using reserved characters', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        '/subfolder images/example image%2C01%2C02.jpeg/',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, '/subfolder images/example image%2C01%2C02.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder%20images/example%20image%252C01%252C02.jpeg?width=200&height=300&format=png&signature=2oAmYelI7UEnvqSSPCfUA25TmS7na1FRVTaxfe5ADyY')
     })
 
     it('returns url with path using a http url', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'http://assets.com/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'http://assets.com/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/http%3A%2F%2Fassets.com%2Fsubfolder%2Fexample.jpeg?width=200&height=300&format=png&signature=MuzfKbHDJY6lzeFQGRcsCS8DzxgL4nCpIowOMFLR1kA')
     })
 
     it('returns url with path using a http url with reserved characters', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'http://assets.com/subfolder/example%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'http://assets.com/subfolder/example%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/http%3A%2F%2Fassets.com%2Fsubfolder%2Fexample%252C01%252C02.jpeg?width=200&height=300&format=png&signature=78e-ysfcy3d0e0rj70QJQ3wpuwI_hAl9ZYxIUVRw62I')
     })
 
     it('returns url with path using a https url', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'https://assets.com/subfolder/example.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'https://assets.com/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/https%3A%2F%2Fassets.com%2Fsubfolder%2Fexample.jpeg?width=200&height=300&format=png&signature=7Dp8Q01u_5YmpmH-j_y4P5vzOn_9EGvh77B3fi2Ke-s')
     })
 
     it('returns url with path using a https url with reserved characters', () => {
-      const url = Url.url(
-        new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT }),
-        'https://assets.com/subfolder/example%2C01%2C02.jpeg',
-        {
-          width: 200,
-          height: 300,
-          format: 'png'
-        }
-      )
+      const url = Url.url(SECURE_SOURCE, 'https://assets.com/subfolder/example%2C01%2C02.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/https%3A%2F%2Fassets.com%2Fsubfolder%2Fexample%252C01%252C02.jpeg?width=200&height=300&format=png&signature=-zvh2hWXP8bHkoJVh8AdJFe9Kqdd1HpP1c2UmuQcYFQ')
     })

From 1edae14fadba40081ce2ec01bcbe07595ddb1d26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Wed, 11 Jan 2023 18:09:56 +0100
Subject: [PATCH 07/15] Add new srcset generation feature

---
 package-lock.json            |    4 +-
 package.json                 |    2 +-
 src/index.js                 |    6 +-
 src/range.js                 |   33 +
 src/sequence.js              |    4 +-
 src/srcset.js                |   58 +
 src/srcset/utils.js          |   77 +
 src/url.js                   |    2 +-
 src/{ => url}/utils.js       |    2 +-
 test/range.test.js           |   44 +
 test/srcset.test.js          | 3294 ++++++++++++++++++++++++++++++++++
 test/srcset/utils.test.js    |  135 ++
 test/url.test.js             |   18 +
 test/{ => url}/utils.test.js |    4 +-
 14 files changed, 3674 insertions(+), 9 deletions(-)
 create mode 100644 src/range.js
 create mode 100644 src/srcset.js
 create mode 100644 src/srcset/utils.js
 rename src/{ => url}/utils.js (96%)
 create mode 100644 test/range.test.js
 create mode 100644 test/srcset.test.js
 create mode 100644 test/srcset/utils.test.js
 rename test/{ => url}/utils.test.js (91%)

diff --git a/package-lock.json b/package-lock.json
index b091150..27506ec 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@imglab/core",
-  "version": "0.2.1",
+  "version": "0.3.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "@imglab/core",
-      "version": "0.2.1",
+      "version": "0.3.0",
       "license": "MIT",
       "devDependencies": {
         "@babel/core": "^7.16.0",
diff --git a/package.json b/package.json
index 9a8017a..ba599e9 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@imglab/core",
   "source": "src/index.js",
-  "version": "0.2.1",
+  "version": "0.3.0",
   "description": "Official imglab Javascript library",
   "main": "dist/index.cjs.js",
   "module": "dist/index.esm.js",
diff --git a/src/index.js b/src/index.js
index 2946751..af46697 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,12 +1,16 @@
 import Url from './url'
+import Srcset from './srcset'
 import Source from './source'
 import Color from './color'
 import Position from './position'
+import Range from './range'
 import Sequence from './sequence'
 
 const url = Url.url
+const srcset = Srcset.srcset
 const color = Color.color
 const position = Position.position
+const range = Range.range
 const sequence = Sequence.sequence
 
-export default { url, Source, color, position, sequence }
+export default { url, srcset, Source, color, position, range, sequence }
diff --git a/src/range.js b/src/range.js
new file mode 100644
index 0000000..be49c9c
--- /dev/null
+++ b/src/range.js
@@ -0,0 +1,33 @@
+export default class Range {
+  #first
+  #last
+  #length
+
+  static range(first, last) {
+    return new Range(first, last)
+  }
+
+  constructor(first, last) {
+    this.#first = first
+    this.#last = last
+    this.#length = Math.abs(this.last - this.first) + 1
+  }
+
+  get first() {
+    return this.#first
+  }
+
+  get last() {
+    return this.#last
+  }
+
+  get length() {
+    return this.#length
+  }
+
+  toArray() {
+    const inc = this.first < this.last ? 1 : -1
+
+    return Array.from({ length: this.length }, (_, i) => this.first + (i * inc))
+  }
+}
diff --git a/src/sequence.js b/src/sequence.js
index 8d4d44d..9ef0467 100644
--- a/src/sequence.js
+++ b/src/sequence.js
@@ -1,7 +1,7 @@
 export default class Sequence {
-  static #DEFAULT_SIZE = 16
+  static DEFAULT_SIZE = 16
 
-  static sequence(first, last, size = Sequence.#DEFAULT_SIZE) {
+  static sequence(first, last, size = Sequence.DEFAULT_SIZE) {
     if (size <= 0) return []
     if (size === 1) return [first]
     if (size === 2) return [first, last]
diff --git a/src/srcset.js b/src/srcset.js
new file mode 100644
index 0000000..5dc162b
--- /dev/null
+++ b/src/srcset.js
@@ -0,0 +1,58 @@
+import Url from './url'
+import Range from './range'
+import Sequence from './sequence'
+import Utils from './srcset/utils'
+
+export default class Srcset {
+  static #DEFAULT_DPRS = [1, 2, 3, 4, 5, 6]
+  static #DEFAULT_WIDTHS = Sequence.sequence(100, 8192)
+
+  static srcset(source, path, params = {}) {
+    params = Utils.normalizeParams(params)
+
+    switch(true) {
+      case Srcset.#isFluid(params.width):
+        if (Srcset.#isFluid(params.dpr)) {
+          throw new Error('dpr as Array or Range is not allowed when width is also an Array or Range')
+        }
+
+        return Srcset.#srcset_width(source, path, params)
+      case !!(params.width || params.height):
+        if (Srcset.#isFluid(params.height)) {
+          throw new Error('height as Array or Range is only allowed when width is also an Array or Range')
+        }
+
+        return Srcset.#srcset_dpr(source, path, {...params, ...{dpr: Srcset.#dprs(params)}})
+      default:
+        if (Srcset.#isFluid(params.dpr)) {
+          throw new Error('dpr as Array or Range is not allowed without specifying width or height')
+        }
+
+        return Srcset.#srcset_width(source, path, {...params, ...{width: Srcset.#DEFAULT_WIDTHS}})
+    }
+  }
+
+  static #dprs(params) {
+    if (Srcset.#isFluid(params.dpr)) {
+      return params.dpr
+    } else {
+      return Srcset.#DEFAULT_DPRS
+    }
+  }
+
+  static #isFluid(value) {
+    return Array.isArray(value) || value instanceof Range
+  }
+
+  static #srcset_dpr(source, path, params) {
+    return Utils.splitParamsDpr(params).map(
+      (splitParams) => `${Url.url(source, path, splitParams)} ${splitParams.dpr}x`
+    ).join(',\n')
+  }
+
+  static #srcset_width(source, path, params) {
+    return Utils.splitParamsWidth(params).map(
+      (splitParams) => `${Url.url(source, path, splitParams)} ${splitParams.width}w`
+    ).join(',\n')
+  }
+}
diff --git a/src/srcset/utils.js b/src/srcset/utils.js
new file mode 100644
index 0000000..71812a9
--- /dev/null
+++ b/src/srcset/utils.js
@@ -0,0 +1,77 @@
+import Range from '../range'
+import Sequence from '../sequence'
+
+export default class Utils {
+  static #NORMALIZE_KEYS = ['dpr', 'width']
+
+  static #SPLIT_DPR_KEYS = ['dpr', 'quality']
+  static #SPLIT_WIDTH_KEYS = ['width', 'height', 'quality']
+
+  static normalizeParams(params) {
+    return Object.entries(params).reduce((normalizedParams, [key, value]) => {
+      return Object.assign(normalizedParams, Utils.#normalizeParam(key, value))
+    }, {})
+  }
+
+  static splitParamsDpr(params) {
+    return Utils.#splitValues(params, Utils.#SPLIT_DPR_KEYS, params.dpr.length).map(
+      ([dpr, quality]) => Utils.#mergeParams(params, {dpr: dpr, quality: quality})
+    )
+  }
+
+  static splitParamsWidth(params) {
+    return Utils.#splitValues(params, Utils.#SPLIT_WIDTH_KEYS, Utils.#splitSize(params.width)).map(
+      ([width, height, quality]) => Utils.#mergeParams(params, {width: width, height: height, quality: quality})
+    )
+  }
+
+  static #normalizeParam(key, value) {
+    switch(true) {
+      case Utils.#NORMALIZE_KEYS.includes(key) && Array.isArray(value) && value.length === 0:
+        return {}
+      default:
+        return { [key]: value }
+    }
+  }
+
+  static #splitSize(value) {
+    switch(true) {
+      case value instanceof Range:
+        return Sequence.DEFAULT_SIZE
+      default:
+        return value.length
+    }
+  }
+
+  static #splitValues(params, keys, size) {
+    return Utils.#zip(keys.map((key) => Utils.#splitValue(key, params[key], size)))
+  }
+
+  static #splitValue(key, value, size) {
+    switch(true) {
+      case key === 'dpr' && value instanceof Range:
+        return value.toArray()
+      case value instanceof Range:
+        return Sequence.sequence(value.first, value.last, size)
+      case Array.isArray(value):
+        return value
+      default:
+        return Array(size).fill(value)
+    }
+  }
+
+  static #zip(arrays) {
+    const length = Math.max(...arrays.map(array => array.length))
+
+    return Array.from({ length: length }, (_, i) => arrays.map(array => array[i]))
+  }
+
+  static #mergeParams(params, mergeParams) {
+    return {
+      ...params,
+      ...Object.fromEntries(
+        Object.entries(mergeParams).filter(([key, _]) => key in params)
+      )
+    }
+  }
+}
diff --git a/src/url.js b/src/url.js
index 685f613..dc9a345 100644
--- a/src/url.js
+++ b/src/url.js
@@ -1,6 +1,6 @@
 import Source from './source'
 import Signature from './signature'
-import Utils from './utils'
+import Utils from './url/utils'
 
 export default class Url {
   static url(source, path, params = {}) {
diff --git a/src/utils.js b/src/url/utils.js
similarity index 96%
rename from src/utils.js
rename to src/url/utils.js
index 71ce87b..5b86ed6 100644
--- a/src/utils.js
+++ b/src/url/utils.js
@@ -33,7 +33,7 @@ export default class Utils {
     switch(true) {
       case key === 'expires' && value instanceof Date:
         return { [key]: Math.floor(value / 1000) }
-      case value === null:
+      case value === undefined || value === null:
         return { [key]: '' }
       default:
         return { [key]: value }
diff --git a/test/range.test.js b/test/range.test.js
new file mode 100644
index 0000000..9edfc25
--- /dev/null
+++ b/test/range.test.js
@@ -0,0 +1,44 @@
+import Range from '../src/range'
+
+describe('Range', () => {
+  describe('constructor', () => {
+    const range = new Range(2, 8)
+
+    expect(range.first).toBe(2)
+    expect(range.last).toBe(8)
+    expect(range.length).toBe(7)
+  })
+
+  describe('first', () => {
+    expect(new Range(0, 1).first).toBe(0)
+    expect(new Range(1, 0).first).toBe(1)
+    expect(new Range(12, 2).first).toBe(12)
+  })
+
+  describe('last', () => {
+    expect(new Range(0, 1).last).toBe(1)
+    expect(new Range(1, 0).last).toBe(0)
+    expect(new Range(12, 2).last).toBe(2)
+  })
+
+  describe('length', () => {
+    expect(new Range(0, 1).length).toBe(2)
+    expect(new Range(1, 0).length).toBe(2)
+    expect(new Range(12, 2).length).toBe(11)
+  })
+
+  describe('toArray', () => {
+    it('returns array with numbers in range', () => {
+      expect(new Range(0, 0).toArray()).toEqual([0])
+      expect(new Range(1, 1).toArray()).toEqual([1])
+      expect(new Range(0, 1).toArray()).toEqual([0, 1])
+      expect(new Range(1, 0).toArray()).toEqual([1, 0])
+      expect(new Range(0, 2).toArray()).toEqual([0, 1, 2])
+      expect(new Range(2, 0).toArray()).toEqual([2, 1, 0])
+      expect(new Range(1, 6).toArray()).toEqual([1, 2, 3, 4, 5, 6])
+      expect(new Range(6, 1).toArray()).toEqual([6, 5, 4, 3, 2, 1])
+      expect(new Range(-2, 2).toArray()).toEqual([-2, -1, 0, 1, 2])
+      expect(new Range(2, -2).toArray()).toEqual([2, 1, 0, -1, -2])
+    })
+  })
+})
diff --git a/test/srcset.test.js b/test/srcset.test.js
new file mode 100644
index 0000000..d17d49d
--- /dev/null
+++ b/test/srcset.test.js
@@ -0,0 +1,3294 @@
+import Srcset from '../src/srcset'
+import Source from '../src/source'
+import Range from '../src/range'
+import Sequence from '../src/sequence'
+
+const range = Range.range
+const sequence = Sequence.sequence
+
+const SECURE_KEY = 'ixUd9is/LDGBw6NPfLCGLjO/WraJlHdytC1+xiIFj22mXAWs/6R6ws4gxSXbDcUHMHv0G+oiTgyfMVsRS2b3'
+const SECURE_SALT = 'c9G9eYKCeWen7vkEyV1cnr4MZkfLI/yo6j72JItzKHjMGDNZKqPFzRtup//qiT51HKGJrAha6Gv2huSFLwJr'
+
+const SOURCE = new Source('assets')
+const SECURE_SOURCE = new Source('assets', { secureKey: SECURE_KEY, secureSalt: SECURE_SALT })
+
+describe('Srcset', () => {
+  describe('srcset using source name', () => {
+    it('returns srcset without params', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg')
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without size params', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { aspectRatio: '16:9', format: 'png' })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with null width', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with undefined width', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with null height', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with undefined height', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without widht, without height and with fixed quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with null quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with undefined quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=72&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=69&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=66&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=63&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=61&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=58&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=56&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=54&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=51&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=49&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=47&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=45&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=43&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=42&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=40&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with empty array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with array of qualities of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=70&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=65&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with fixed width', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and null dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and undefined dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and range of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x'
+      )
+    })
+
+    it('returns srcset with fixed width and empty array of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x')
+    })
+
+    it('returns srcset with fixed width and array of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and null quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and undefined quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=66&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=58&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=51&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=45&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=40&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and empty array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=70&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=65&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&quality=61 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&quality=49 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&quality=40 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&quality=70 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&quality=65 3x'
+      )
+    })
+
+    it('returns srcset with fixed height', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and fixed dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and null dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and undefined dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and range of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x'
+      )
+    })
+
+    it('returns srcset with fixed height and empty array of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x')
+    })
+
+    it('returns srcset with fixed height and array of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x'
+      )
+    })
+
+    it('returns srcset with fixed height and fixed quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and null quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and undefined quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=66&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=58&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=51&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=45&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=40&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and empty array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=70&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=65&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&quality=61 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&quality=49 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&quality=40 4x'
+      )
+    })
+
+    it('returns srcset with fixed height, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { height: 200, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&quality=70 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&quality=65 3x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed height', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and fixed dpr', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and range of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and empty array of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x')
+    })
+
+    it('returns srcset with fixed width, fixed height and array of dprs', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and fixed quality', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=66&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=58&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=51&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=45&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=40&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and empty array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=70&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=65&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&quality=61 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&quality=49 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&quality=40 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: 200, height: 300, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&quality=70 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&quality=65 3x'
+      )
+    })
+
+    it('returns srcset with range of widths', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: range(100, 4096) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=128 128w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=164 164w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=269 269w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=345 345w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=566 566w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=724 724w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1188 1188w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1522 1522w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2497 2497w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3198 3198w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096 4096w'
+      )
+    })
+
+    it('returns srcset with range of widths and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: range(100, 4096), quality: range(70, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&quality=70 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=128&quality=67 128w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=164&quality=65 164w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&quality=63 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=269&quality=60 269w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=345&quality=58 345w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&quality=56 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=566&quality=54 566w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=724&quality=52 724w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&quality=50 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1188&quality=48 1188w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1522&quality=46 1522w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&quality=45 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2497&quality=43 2497w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3198&quality=42 3198w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&quality=40 4096w'
+      )
+    })
+
+    it('returns srcset with sequence of widths', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: sequence(100, 4096, 6) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096 4096w'
+      )
+    })
+
+    it('returns srcset with sequence of widths and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: sequence(100, 4096, 6), quality: range(70, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&quality=70 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&quality=63 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&quality=56 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&quality=50 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&quality=45 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&quality=40 4096w'
+      )
+    })
+
+    it('returns srcset with empty array of widths', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with array of widths of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200 200w')
+    })
+
+    it('returns srcset with array of widths', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and range of heights', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], height: range(300, 500) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=387 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and empty array of heights', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], height: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height= 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of heights of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], height: [300] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of heights', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], height: [300, 400, 500] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=400 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=55 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=40 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and empty array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality= 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=70 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=65 400w'
+      )
+    })
+
+    it('returns srcset with array of widths, range of heights and range of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], height: range(300, 500), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=387&quality=55 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&quality=40 400w'
+      )
+    })
+
+    it('returns srcset with array of widths, array of heights and array of qualities', () => {
+      const srcset = Srcset.srcset('assets', 'example.jpeg', { width: [200, 300, 400], height: [300, 400, 500], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=400&quality=70 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&quality=65 400w'
+      )
+    })
+
+    it('throws a new error when width is fluid and dpr is also fluid', () => {
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: range(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: range(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: [100, 200, 300], dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: [100, 200, 300], dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: sequence(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: sequence(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+    })
+
+    it('throws a new error when width is not fluid and height is fluid', () => {
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { height: range(100, 300) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { height: [100, 200, 300] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: 100, height: range(100, 300) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { width: 100, height: [100, 200, 300] }) }).toThrow(Error)
+    })
+
+    it('throws a new error when width and height are not specified and dpr is fluid', () => {
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset('assets', 'example.jpeg', { dpr: [1, 2, 3] }) }).toThrow(Error)
+    })
+  })
+
+  describe('srcset using source', () => {
+    it('returns srcset without params', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg')
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without size params', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { aspectRatio: '16:9', format: 'png' })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with null width', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with undefined width', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with null height', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with undefined height', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without widht, without height and with fixed quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with null quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with undefined quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=72&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=69&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=66&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=63&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=61&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=58&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=56&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=54&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=51&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=49&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=47&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=45&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=43&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=42&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=40&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with empty array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=70&width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=65&width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with fixed width', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and null dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and undefined dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and range of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x'
+      )
+    })
+
+    it('returns srcset with fixed width and empty array of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x')
+    })
+
+    it('returns srcset with fixed width and array of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3 3x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and null quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and undefined quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=66&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=58&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=51&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=45&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=40&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=70&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=65&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&quality=61 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&quality=49 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&quality=40 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, list of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&quality=70 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&quality=65 3x'
+      )
+    })
+
+    it('returns srcset with fixed height', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and fixed dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and null dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and undefined dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and range of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x'
+      )
+    })
+
+    it('returns srcset with fixed height and empty array of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x')
+    })
+
+    it('returns srcset with fixed height and array of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3 3x'
+      )
+    })
+
+    it('returns srcset with fixed height and fixed quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and null quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and undefined quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=66&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=58&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=51&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=45&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=40&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=70&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=65&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed height, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&quality=61 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&quality=49 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&quality=40 4x'
+      )
+    })
+
+    it('returns srcset with fixed height, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { height: 200, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&quality=70 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&quality=65 3x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed height', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and fixed dpr', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and range of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array list of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x')
+    })
+
+    it('returns srcset with fixed width, fixed height and array of dprs', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3 3x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and fixed quality', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=66&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=58&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=51&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=45&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=40&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=70&dpr=2 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=65&dpr=3 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&quality=61 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&quality=49 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&quality=40 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height, array of dprs and arry of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&quality=75 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&quality=70 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&quality=65 3x'
+      )
+    })
+
+    it('returns srcset with range of widths', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: range(100, 4096) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=128 128w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=164 164w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=269 269w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=345 345w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=566 566w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=724 724w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1188 1188w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1522 1522w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2497 2497w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3198 3198w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096 4096w'
+      )
+    })
+
+    it('returns srcset with range of widths and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: range(100, 4096), quality: range(70, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&quality=70 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=128&quality=67 128w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=164&quality=65 164w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&quality=63 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=269&quality=60 269w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=345&quality=58 345w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&quality=56 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=566&quality=54 566w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=724&quality=52 724w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&quality=50 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1188&quality=48 1188w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1522&quality=46 1522w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&quality=45 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2497&quality=43 2497w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3198&quality=42 3198w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&quality=40 4096w'
+      )
+    })
+
+    it('returns srcset with sequence of widths', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: sequence(100, 4096, 6) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096 4096w'
+      )
+    })
+
+    it('returns srcset with sequence of widths and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: sequence(100, 4096, 6), quality: range(70, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&quality=70 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&quality=63 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&quality=56 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&quality=50 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&quality=45 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&quality=40 4096w'
+      )
+    })
+
+    it('returns srcset with empty array of widths', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192 8192w'
+      )
+    })
+
+    it('returns srcset with array of widths of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200 200w')
+    })
+
+    it('returns srcset with array of widths', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and range of heights', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], height: range(300, 500) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=387 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and empty array of heights', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height= 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of heights of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [300] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of heights', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [300, 400, 500] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=400 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=55 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=40 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality= 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality= 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality= 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=70 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=65 400w'
+      )
+    })
+
+    it('returns srcset with array of widths, range of heights and range of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], height: range(300, 500), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=387&quality=55 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&quality=40 400w'
+      )
+    })
+
+    it('returns srcset with array of widths, array of heights and array of qualities', () => {
+      const srcset = Srcset.srcset(SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [300, 400, 500], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=400&quality=70 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&quality=65 400w'
+      )
+    })
+
+    it('throws a new error when width is fluid and dpr is also fluid', () => {
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: range(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: range(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+    })
+
+    it('throws a new error when width is not fluid and height is fluid', () => {
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { height: range(100, 300) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { height: [100, 200, 300] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: 100, height: range(100, 300) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { width: 100, height: [100, 200, 300] }) }).toThrow(Error)
+    })
+
+    it('throws a new error when width and height are not specified and dpr is fluid', () => {
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SOURCE, 'example.jpeg', { dpr: [1, 2, 3] }) }).toThrow(Error)
+    })
+  })
+
+  describe('srcset using secure source', () => {
+    it('returns srcset without params', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg')
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&signature=-G7slD-ae7GdT1lx8I0-7iUMnkMTU3NcTGB8GzaiaNg 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134&signature=fHLmra9mxfjnp8E-7Cj7AZlJ43kRKLILUQ3Gawa0pxA 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180&signature=omMuwPcMxKVGGnDk9sR2G6qD28uLIAldc-N9FvhwSH0 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241&signature=09nboU72WGyryf9zyxMsNyBNu4PUrrGkuDlbM6shYas 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324&signature=KOLqtvfSwSLUKnWY5-tvuaj-pOsBcN_WIHRTNLpJ7-Y 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434&signature=48LOvc3n4CqstYfikmhT57XvKnydLRUa6qT-_IqZ0io 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583&signature=IfEEELQp0__u7Ip-qzKQ2Plw70ybDOdrVeOz5jw9BOY 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781&signature=p6sa4yVVce8AkuJagwLolgRD1nQUyzZsMw68KSQaVwM 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048&signature=qz5KgcQRJHnCcubs9ldfGUGm1vzsvjBge17OWhykwp0 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406&signature=Kh16qduc4dixmTKuhASbspncSVHlDTd4DnsbcmfB6Mw 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886&signature=WN-YBqlX-bhiWxFydOVBsfkVIWjIuz09qvHkA2UZWvs 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530&signature=wH5aHb7P0S6xuJvBDoPgZPIo2-nosgViwt2ADVGhAvw 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394&signature=e_fi5Y-uruuUWips4wxJt5WkHKETn9P1MmHXVD9Cvxs 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553&signature=AuXvD4c7FN279MOC63ogznGAqYmHqLCVDgQvl0I1IKM 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107&signature=nWDdC0v7d695Oo_bdhgc_AkxCkIyF7FSZgj7bAcOkNo 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192&signature=HNmtIa6jhuc8o3Yir2zZBjDvgiiAwGeMzM-x7ow1dSE 8192w'
+      )
+    })
+
+    it('returns srcset without size params', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { aspectRatio: '16:9', format: 'png' })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=100&signature=NbJJwFNLXH2Lm04Vlq0bx4mQx8CAR4N_abDW4dGpPh8 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=134&signature=YReBU7g45tkZKQcSM0KCJHEBgy98F10a4ndYE5RAYZE 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=180&signature=cOHBLDWqFJYn3G5wSy7h10EbClkHU0pPk3vF6306hew 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=241&signature=RNLjPSNlme7d3UgJkuFScYmjquG1pWALFZcQmNcFaDs 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=324&signature=Oui_yhAccLk3qvOjb2BsPcItb4OQKRmdmEfEXO5RGf0 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=434&signature=yjSD343Tj-8iIUTCyhrTN0sgScsKOeZgRzwHRh0lbBk 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=583&signature=gPV3Gms4q38hj93EhxL1Ho0ZC-GkEDSuHbzs624eDyo 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=781&signature=69h4C_4odnjjo9DTDU8esuM9kDCPqSui8h1OFQH3GMs 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1048&signature=5ULJml6M2hoExOZ20Ki1nt7dtqvvNSffb33iInBZocc 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1406&signature=3aGhzUlEYZhMywzE5vfNphpJAtZWU0L-P3i6k26Fqvo 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=1886&signature=B2b4-1PIflt5BDQfcIm6G0OxLxQFNavbORPkukVuhPc 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=2530&signature=HjNxP9QSHyEP6iDZv1TgbGoNHRb57ncfPYdVWPawYgM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=3394&signature=Rv1AyIY0-IGNb6G8cPOdRBmm6l3HB0cPYoL66qCcnhc 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=4553&signature=Ct7Kh3NAf8MZ_NsalXBymsdhrcF-BoKnwblXKNXQuGY 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=6107&signature=JazBYsfM0U0RJV0SdbbGBZznDRT6bHd8_Kc6uinl4Hs 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?aspect-ratio=16%3A9&format=png&width=8192&signature=-JvRN7tWRXGNDc1KABnZv5RmZ_FgTUsOUum3XXF1fxE 8192w'
+      )
+    })
+
+    it('returns srcset with null width', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&signature=-G7slD-ae7GdT1lx8I0-7iUMnkMTU3NcTGB8GzaiaNg 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134&signature=fHLmra9mxfjnp8E-7Cj7AZlJ43kRKLILUQ3Gawa0pxA 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180&signature=omMuwPcMxKVGGnDk9sR2G6qD28uLIAldc-N9FvhwSH0 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241&signature=09nboU72WGyryf9zyxMsNyBNu4PUrrGkuDlbM6shYas 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324&signature=KOLqtvfSwSLUKnWY5-tvuaj-pOsBcN_WIHRTNLpJ7-Y 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434&signature=48LOvc3n4CqstYfikmhT57XvKnydLRUa6qT-_IqZ0io 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583&signature=IfEEELQp0__u7Ip-qzKQ2Plw70ybDOdrVeOz5jw9BOY 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781&signature=p6sa4yVVce8AkuJagwLolgRD1nQUyzZsMw68KSQaVwM 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048&signature=qz5KgcQRJHnCcubs9ldfGUGm1vzsvjBge17OWhykwp0 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406&signature=Kh16qduc4dixmTKuhASbspncSVHlDTd4DnsbcmfB6Mw 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886&signature=WN-YBqlX-bhiWxFydOVBsfkVIWjIuz09qvHkA2UZWvs 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530&signature=wH5aHb7P0S6xuJvBDoPgZPIo2-nosgViwt2ADVGhAvw 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394&signature=e_fi5Y-uruuUWips4wxJt5WkHKETn9P1MmHXVD9Cvxs 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553&signature=AuXvD4c7FN279MOC63ogznGAqYmHqLCVDgQvl0I1IKM 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107&signature=nWDdC0v7d695Oo_bdhgc_AkxCkIyF7FSZgj7bAcOkNo 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192&signature=HNmtIa6jhuc8o3Yir2zZBjDvgiiAwGeMzM-x7ow1dSE 8192w'
+      )
+    })
+
+    it('returns srcset with undefined width', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&signature=-G7slD-ae7GdT1lx8I0-7iUMnkMTU3NcTGB8GzaiaNg 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134&signature=fHLmra9mxfjnp8E-7Cj7AZlJ43kRKLILUQ3Gawa0pxA 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180&signature=omMuwPcMxKVGGnDk9sR2G6qD28uLIAldc-N9FvhwSH0 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241&signature=09nboU72WGyryf9zyxMsNyBNu4PUrrGkuDlbM6shYas 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324&signature=KOLqtvfSwSLUKnWY5-tvuaj-pOsBcN_WIHRTNLpJ7-Y 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434&signature=48LOvc3n4CqstYfikmhT57XvKnydLRUa6qT-_IqZ0io 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583&signature=IfEEELQp0__u7Ip-qzKQ2Plw70ybDOdrVeOz5jw9BOY 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781&signature=p6sa4yVVce8AkuJagwLolgRD1nQUyzZsMw68KSQaVwM 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048&signature=qz5KgcQRJHnCcubs9ldfGUGm1vzsvjBge17OWhykwp0 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406&signature=Kh16qduc4dixmTKuhASbspncSVHlDTd4DnsbcmfB6Mw 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886&signature=WN-YBqlX-bhiWxFydOVBsfkVIWjIuz09qvHkA2UZWvs 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530&signature=wH5aHb7P0S6xuJvBDoPgZPIo2-nosgViwt2ADVGhAvw 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394&signature=e_fi5Y-uruuUWips4wxJt5WkHKETn9P1MmHXVD9Cvxs 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553&signature=AuXvD4c7FN279MOC63ogznGAqYmHqLCVDgQvl0I1IKM 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107&signature=nWDdC0v7d695Oo_bdhgc_AkxCkIyF7FSZgj7bAcOkNo 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192&signature=HNmtIa6jhuc8o3Yir2zZBjDvgiiAwGeMzM-x7ow1dSE 8192w'
+      )
+    })
+
+    it('returns srcset with null height', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=100&signature=qgGwAacGLubPw_MV9gGsqSQxZwwwF6o3xrhsF7oZzeo 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=134&signature=A1X1Ufip8Y3a-Kx8RSbr3BKPK7sTokKuFQrY-Xa_24c 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=180&signature=yXqfS97rINsU0CSax5otWFNKMmvkrAPpRxobREUtdSs 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=241&signature=_Ugb6sjZCvH7O5Pz2JMFqacKrBOFz_3vsLxjTF9kclo 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=324&signature=sAIh1BhsFC1DyHWF0CFh0a-LAcy_loT2ElJspyC7vqY 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=434&signature=H02oPLw1sbftKYXoJc5AXH1cKWIXUzACNpiVxM-GUyY 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=583&signature=R8xJ-AkDk_zaTYM5ED7TgvQWTLwA5cZLs_jyuQGCiZk 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=781&signature=7PmZrtuoJOmMat6De-t8ymptJu9n9FQ7Gxn7pa2piW8 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1048&signature=F8lJX64AcJfvss69fZbINKoPd7cbKHCRlYjX1z1_dsg 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1406&signature=txn8esJ7vIqkgkZvwdKRSS53E3uf-7j1Yb8f0dIRlw4 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1886&signature=wR2DposN7ibU8Dl9MzzjePe9AWVK1ox4xVV4CQ0OghY 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=2530&signature=zeDRRPL4BFfFg_rtCXTeFmsTT_C9kM0ntAghLVoazTs 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=3394&signature=CLIANKNBnTruPtrwmcbE8dqKgi5ft_ffTM2mH8kNvFo 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=4553&signature=Dn-shQtSttRLPh0j3fbUte7JkwWy4--nXbRJON0Dcqs 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=6107&signature=3F0v4wxNyoSunFplHbQps4EeLuQCLtVxDXfEi_GTYNE 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=8192&signature=ZhwS0bA6DmRns1bv1FuLw9r1Fg8Y46JixHRgvpiiwhw 8192w'
+      )
+    })
+
+    it('returns srcset with undefined height', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=100&signature=qgGwAacGLubPw_MV9gGsqSQxZwwwF6o3xrhsF7oZzeo 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=134&signature=A1X1Ufip8Y3a-Kx8RSbr3BKPK7sTokKuFQrY-Xa_24c 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=180&signature=yXqfS97rINsU0CSax5otWFNKMmvkrAPpRxobREUtdSs 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=241&signature=_Ugb6sjZCvH7O5Pz2JMFqacKrBOFz_3vsLxjTF9kclo 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=324&signature=sAIh1BhsFC1DyHWF0CFh0a-LAcy_loT2ElJspyC7vqY 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=434&signature=H02oPLw1sbftKYXoJc5AXH1cKWIXUzACNpiVxM-GUyY 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=583&signature=R8xJ-AkDk_zaTYM5ED7TgvQWTLwA5cZLs_jyuQGCiZk 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=781&signature=7PmZrtuoJOmMat6De-t8ymptJu9n9FQ7Gxn7pa2piW8 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1048&signature=F8lJX64AcJfvss69fZbINKoPd7cbKHCRlYjX1z1_dsg 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1406&signature=txn8esJ7vIqkgkZvwdKRSS53E3uf-7j1Yb8f0dIRlw4 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=1886&signature=wR2DposN7ibU8Dl9MzzjePe9AWVK1ox4xVV4CQ0OghY 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=2530&signature=zeDRRPL4BFfFg_rtCXTeFmsTT_C9kM0ntAghLVoazTs 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=3394&signature=CLIANKNBnTruPtrwmcbE8dqKgi5ft_ffTM2mH8kNvFo 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=4553&signature=Dn-shQtSttRLPh0j3fbUte7JkwWy4--nXbRJON0Dcqs 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=6107&signature=3F0v4wxNyoSunFplHbQps4EeLuQCLtVxDXfEi_GTYNE 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=&width=8192&signature=ZhwS0bA6DmRns1bv1FuLw9r1Fg8Y46JixHRgvpiiwhw 8192w'
+      )
+    })
+
+    it('returns srcset without widht, without height and with fixed quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100&signature=MdlVEFrlbd_uNGEjZM1ALuGWIS-cZl1DGDhSDvDhato 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=134&signature=pSG9vgEsdniuyEUZ8r0Wfd_CNgFvbDmtUayIwPXTsPg 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=180&signature=291PUFY7rMNz2DxtTY5dcGxGYiwRnJD7ye7tgf-GZ8Y 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=241&signature=qn_UwdsTfRFtk-yq8arB5yo41372mzsdh26-AYAqMHQ 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=324&signature=8XELAadBAAFYQnae37ObGZA49oE8W9b5yF_pY3QVJQY 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=434&signature=U6NzmJJxrXm4KRyWZqQL6LwSVF4HygXHT_vYfvQI5xI 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=583&signature=XkXvyNCm4KUHS-fLzepPC1603et-ew3PH3CN_tQD6n8 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=781&signature=iPlNimegR3djYwTchz85-KFPY93d8aMTKcpzrzKNbKs 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1048&signature=Ftqj-AGOCC0acyBIo18V8Epm6g82tiuHvq8I_djY0Ks 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1406&signature=BsjFTuWi9ilETulFFJB-IEdxw-e_CWRBgnlDImz6-gc 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=1886&signature=E2TXXvpUm5eyljOQ7uG3i73ok1XBBLsm6AqW5zVTmN4 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=2530&signature=Dh7vfyl2hBMd1cD6YTJkHbmcA-0ZCi06HigvPaIlFSM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=3394&signature=zHRSwjveBPRWo03Dn9dN7zjrewa7FpfF3Wb9aUi7bYM 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=4553&signature=yLwCeLEr1CHxb_zuPQSSbssejnsdGNqNLdTOj1D4ZsA 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=6107&signature=2GEzlHKTq98nTa5ObpB6-ARv8q8W-uHm19Vumzz-k2I 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=8192&signature=ShTkNRkOycgMAkCOKln6DPFCjM2673LNGaZPI2omGbo 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with null quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100&signature=vyUqI3Rk41lOSzhE0HAwl73gOfN6ERg6OOmq9Ysa1SU 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134&signature=uy5848AZSPUeFGwSV27yLlGclqYU1oBpo1rsOow-pNo 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180&signature=Ozgkx_JvAEICkszdoclwuWmZ5BEjyIDVZJNDl_O0aqg 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241&signature=Jf9HPL2I0D9zNDGALITPlbMapmO1-aUsbiM5FqnczFc 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324&signature=ff6JAgBW2sAPl1PfQGwkLPWUEkzfQts4mUe-bFLZ3Ec 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434&signature=GldXfzEEI2N6SZk9IbeXLPxMlRcSRoEWO8e3Zpp8PH8 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583&signature=5ebKNVmrlDGyQQVQcjbk0vAvmU_l1jtSpHkMxFxlbBw 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781&signature=jJd3B8wzvTjwqIFHmB4ZXLHonbw-EQLCiE6TiHRT0tw 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048&signature=DAxsrxK-VqaF-QaEoZru83yuhX2MV5oakelAn8-Jpb8 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406&signature=UHqCY93GXmZh9WmR3ZypL-nv4mpcexghu2LXlUiLv10 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886&signature=b6PhbtD5_uFpHj1VFCbP4_06ZhhZOBlYH-p0mGub8yI 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530&signature=3XIFh6uFYxgO7yNh_6EmQ7cZp9UMYsB0AdRzpaebvSM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394&signature=gKVMiRqju-04c5xloACa4Wb1qYR2_zLtk00Cu5ZDIzI 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553&signature=jRUdh9g9bPeALalAepKCSBwr2bSU3mI5jS7HMaekhyc 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107&signature=nCkD13Of8MMZpopYN4RSEsZwhLNT3dsi3AFarXaPKTU 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192&signature=Ax9PBsp9q8KWyQiFyFaOnKdxWN6aY9RFWZpTE_sj9iQ 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with undefined quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100&signature=vyUqI3Rk41lOSzhE0HAwl73gOfN6ERg6OOmq9Ysa1SU 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134&signature=uy5848AZSPUeFGwSV27yLlGclqYU1oBpo1rsOow-pNo 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180&signature=Ozgkx_JvAEICkszdoclwuWmZ5BEjyIDVZJNDl_O0aqg 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241&signature=Jf9HPL2I0D9zNDGALITPlbMapmO1-aUsbiM5FqnczFc 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324&signature=ff6JAgBW2sAPl1PfQGwkLPWUEkzfQts4mUe-bFLZ3Ec 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434&signature=GldXfzEEI2N6SZk9IbeXLPxMlRcSRoEWO8e3Zpp8PH8 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583&signature=5ebKNVmrlDGyQQVQcjbk0vAvmU_l1jtSpHkMxFxlbBw 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781&signature=jJd3B8wzvTjwqIFHmB4ZXLHonbw-EQLCiE6TiHRT0tw 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048&signature=DAxsrxK-VqaF-QaEoZru83yuhX2MV5oakelAn8-Jpb8 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406&signature=UHqCY93GXmZh9WmR3ZypL-nv4mpcexghu2LXlUiLv10 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886&signature=b6PhbtD5_uFpHj1VFCbP4_06ZhhZOBlYH-p0mGub8yI 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530&signature=3XIFh6uFYxgO7yNh_6EmQ7cZp9UMYsB0AdRzpaebvSM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394&signature=gKVMiRqju-04c5xloACa4Wb1qYR2_zLtk00Cu5ZDIzI 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553&signature=jRUdh9g9bPeALalAepKCSBwr2bSU3mI5jS7HMaekhyc 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107&signature=nCkD13Of8MMZpopYN4RSEsZwhLNT3dsi3AFarXaPKTU 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192&signature=Ax9PBsp9q8KWyQiFyFaOnKdxWN6aY9RFWZpTE_sj9iQ 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100&signature=MdlVEFrlbd_uNGEjZM1ALuGWIS-cZl1DGDhSDvDhato 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=72&width=134&signature=Fh2C6Vf_0ivpN4fANWjW3yBUSseFL7kLEnQ9AqUh_94 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=69&width=180&signature=5UBJKCNaufIBc9SXsQTv_0vA9ADGPBvNAxInQZYfcVk 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=66&width=241&signature=t8trQBaYqW9xzz9bFEcW__1yfGLqEeacpZyfGauGvc0 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=63&width=324&signature=yhbdd6qiTmJmCX_PobKv_5zwMp1RDACCMvKkDhXRBVY 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=61&width=434&signature=yGYu0jjKy6r6aygEWC-ew85-6xTcVTtsvR1Cb1qF9OM 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=58&width=583&signature=N0ItLybI-R3NFwOtYQZMfbRzIVfiuEd5XFW39rZwxiA 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=56&width=781&signature=7UX9-2xa32IHajJgzeNC-q2ut9bWGHYFAAR-f5TclUc 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=54&width=1048&signature=LTqNlXbgql-IlWCjZ_NDE4upRfP2edc0hW5Lnm17AH8 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=51&width=1406&signature=xDju3Exs-kzpaU9gWcUdShhiygjxu2zsuSNnP7aOpLM 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=49&width=1886&signature=F49-uX9mQaAlieoq32QY-gv1JOwAzo_8DTRM54Blm7w 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=47&width=2530&signature=dl3xzdKQDwPTAMC2X35P4oWPvLhKj2CqHYtMsadeJxU 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=45&width=3394&signature=Qk7S4REwQNBocNQL4Lr-urMOVljtB8AAWmiXYSrYkV0 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=43&width=4553&signature=gzFsF5t-vOZbmzQcaDnFk058hzFFATqWI7eZ9FFCa20 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=42&width=6107&signature=h8T3dTy7tWObEYVzFHb_Nre8rfSTidhqCcUPNnO7-9E 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=40&width=8192&signature=nw1YyvOX5-5QGR_WAlj-f7Y0j69LS68wXKbv-JiNZXs 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with empty array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=100&signature=vyUqI3Rk41lOSzhE0HAwl73gOfN6ERg6OOmq9Ysa1SU 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134&signature=uy5848AZSPUeFGwSV27yLlGclqYU1oBpo1rsOow-pNo 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180&signature=Ozgkx_JvAEICkszdoclwuWmZ5BEjyIDVZJNDl_O0aqg 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241&signature=Jf9HPL2I0D9zNDGALITPlbMapmO1-aUsbiM5FqnczFc 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324&signature=ff6JAgBW2sAPl1PfQGwkLPWUEkzfQts4mUe-bFLZ3Ec 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434&signature=GldXfzEEI2N6SZk9IbeXLPxMlRcSRoEWO8e3Zpp8PH8 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583&signature=5ebKNVmrlDGyQQVQcjbk0vAvmU_l1jtSpHkMxFxlbBw 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781&signature=jJd3B8wzvTjwqIFHmB4ZXLHonbw-EQLCiE6TiHRT0tw 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048&signature=DAxsrxK-VqaF-QaEoZru83yuhX2MV5oakelAn8-Jpb8 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406&signature=UHqCY93GXmZh9WmR3ZypL-nv4mpcexghu2LXlUiLv10 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886&signature=b6PhbtD5_uFpHj1VFCbP4_06ZhhZOBlYH-p0mGub8yI 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530&signature=3XIFh6uFYxgO7yNh_6EmQ7cZp9UMYsB0AdRzpaebvSM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394&signature=gKVMiRqju-04c5xloACa4Wb1qYR2_zLtk00Cu5ZDIzI 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553&signature=jRUdh9g9bPeALalAepKCSBwr2bSU3mI5jS7HMaekhyc 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107&signature=nCkD13Of8MMZpopYN4RSEsZwhLNT3dsi3AFarXaPKTU 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192&signature=Ax9PBsp9q8KWyQiFyFaOnKdxWN6aY9RFWZpTE_sj9iQ 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100&signature=MdlVEFrlbd_uNGEjZM1ALuGWIS-cZl1DGDhSDvDhato 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=134&signature=uy5848AZSPUeFGwSV27yLlGclqYU1oBpo1rsOow-pNo 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=180&signature=Ozgkx_JvAEICkszdoclwuWmZ5BEjyIDVZJNDl_O0aqg 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241&signature=Jf9HPL2I0D9zNDGALITPlbMapmO1-aUsbiM5FqnczFc 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324&signature=ff6JAgBW2sAPl1PfQGwkLPWUEkzfQts4mUe-bFLZ3Ec 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434&signature=GldXfzEEI2N6SZk9IbeXLPxMlRcSRoEWO8e3Zpp8PH8 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583&signature=5ebKNVmrlDGyQQVQcjbk0vAvmU_l1jtSpHkMxFxlbBw 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781&signature=jJd3B8wzvTjwqIFHmB4ZXLHonbw-EQLCiE6TiHRT0tw 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048&signature=DAxsrxK-VqaF-QaEoZru83yuhX2MV5oakelAn8-Jpb8 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406&signature=UHqCY93GXmZh9WmR3ZypL-nv4mpcexghu2LXlUiLv10 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886&signature=b6PhbtD5_uFpHj1VFCbP4_06ZhhZOBlYH-p0mGub8yI 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530&signature=3XIFh6uFYxgO7yNh_6EmQ7cZp9UMYsB0AdRzpaebvSM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394&signature=gKVMiRqju-04c5xloACa4Wb1qYR2_zLtk00Cu5ZDIzI 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553&signature=jRUdh9g9bPeALalAepKCSBwr2bSU3mI5jS7HMaekhyc 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107&signature=nCkD13Of8MMZpopYN4RSEsZwhLNT3dsi3AFarXaPKTU 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192&signature=Ax9PBsp9q8KWyQiFyFaOnKdxWN6aY9RFWZpTE_sj9iQ 8192w'
+      )
+    })
+
+    it('returns srcset without width, without height and with array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?quality=75&width=100&signature=MdlVEFrlbd_uNGEjZM1ALuGWIS-cZl1DGDhSDvDhato 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=70&width=134&signature=JJ1R-D0Y2uIxbuGndKiD9ybH7nCvqrH-AFCMEJ0wFFY 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=65&width=180&signature=gfTHds7_QB0Jw68RnDs1D3Hwq_MQ934IJsovJ9ewFOU 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=241&signature=Jf9HPL2I0D9zNDGALITPlbMapmO1-aUsbiM5FqnczFc 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=324&signature=ff6JAgBW2sAPl1PfQGwkLPWUEkzfQts4mUe-bFLZ3Ec 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=434&signature=GldXfzEEI2N6SZk9IbeXLPxMlRcSRoEWO8e3Zpp8PH8 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=583&signature=5ebKNVmrlDGyQQVQcjbk0vAvmU_l1jtSpHkMxFxlbBw 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=781&signature=jJd3B8wzvTjwqIFHmB4ZXLHonbw-EQLCiE6TiHRT0tw 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1048&signature=DAxsrxK-VqaF-QaEoZru83yuhX2MV5oakelAn8-Jpb8 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1406&signature=UHqCY93GXmZh9WmR3ZypL-nv4mpcexghu2LXlUiLv10 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=1886&signature=b6PhbtD5_uFpHj1VFCbP4_06ZhhZOBlYH-p0mGub8yI 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=2530&signature=3XIFh6uFYxgO7yNh_6EmQ7cZp9UMYsB0AdRzpaebvSM 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=3394&signature=gKVMiRqju-04c5xloACa4Wb1qYR2_zLtk00Cu5ZDIzI 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=4553&signature=jRUdh9g9bPeALalAepKCSBwr2bSU3mI5jS7HMaekhyc 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=6107&signature=nCkD13Of8MMZpopYN4RSEsZwhLNT3dsi3AFarXaPKTU 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?quality=&width=8192&signature=Ax9PBsp9q8KWyQiFyFaOnKdxWN6aY9RFWZpTE_sj9iQ 8192w'
+      )
+    })
+
+    it('returns srcset with fixed width', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&signature=M3Jtp4O7QfsDJkCEiC48pRrscdCp8Pw_qz5l_HwfTdg 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5&signature=65EB3f_-13GfS8Sfq_cQ1AHCkSmDYgaWkeFCF69vwEw 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6&signature=1H6iBT7iifEFXYFdg016xjF0HnQljOki5z4acr2kRF0 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&signature=M3Jtp4O7QfsDJkCEiC48pRrscdCp8Pw_qz5l_HwfTdg 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5&signature=65EB3f_-13GfS8Sfq_cQ1AHCkSmDYgaWkeFCF69vwEw 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6&signature=1H6iBT7iifEFXYFdg016xjF0HnQljOki5z4acr2kRF0 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and null dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&signature=M3Jtp4O7QfsDJkCEiC48pRrscdCp8Pw_qz5l_HwfTdg 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5&signature=65EB3f_-13GfS8Sfq_cQ1AHCkSmDYgaWkeFCF69vwEw 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6&signature=1H6iBT7iifEFXYFdg016xjF0HnQljOki5z4acr2kRF0 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and undefined dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&signature=M3Jtp4O7QfsDJkCEiC48pRrscdCp8Pw_qz5l_HwfTdg 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5&signature=65EB3f_-13GfS8Sfq_cQ1AHCkSmDYgaWkeFCF69vwEw 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6&signature=1H6iBT7iifEFXYFdg016xjF0HnQljOki5z4acr2kRF0 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and range of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&signature=M3Jtp4O7QfsDJkCEiC48pRrscdCp8Pw_qz5l_HwfTdg 4x'
+      )
+    })
+
+    it('returns srcset with fixed width and empty array of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&signature=M3Jtp4O7QfsDJkCEiC48pRrscdCp8Pw_qz5l_HwfTdg 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=5&signature=65EB3f_-13GfS8Sfq_cQ1AHCkSmDYgaWkeFCF69vwEw 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=6&signature=1H6iBT7iifEFXYFdg016xjF0HnQljOki5z4acr2kRF0 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x')
+    })
+
+    it('returns srcset with fixed width and array of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&signature=Dt2QjQRTGriKiEL8b4bd1oR0s4kk_YR-t5ip9FG_8r4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&signature=ENOlJPVnPCsCl7xWghj4y-jeBPHvSaK9LG5r9gvf_14 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&signature=Kx4REMpTxLA00Wt-NWM9dw8wML441Ok0C1nmATDVcho 3x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1&signature=zf8CQyXlM8escASLnzgE-Ty32cv2LCoVMiC34IxGVZQ 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=2&signature=34do97OeAJKHeTdqcPLM0EVlzolbA0bWmBWCogQH3Hs 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=3&signature=M9uchI7N8SsJj1NWAjwkGFarhewbwn-PuJZuVvoAO9s 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=4&signature=i7zW4GGDKP4a5z65hGb2TlqdnvBQbeEr40JAn8PhEZg 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=5&signature=1hi15abMQlRMLXxERtnG2aecaHkXrBG8WUXbEEDjbyk 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=6&signature=TZg-SVdMxQbJW1jQuhU35-wQok0k3Y_pj3zBqIOz_J4 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and null quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1&signature=tgqva0giYvsn-FKsRYIO8d9Tm4iS85St8_ilDzFCoA4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2&signature=blj1DwMwrUc8ZhdT-7_uExNG5PSobt3955CpsZ01SGs 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3&signature=j5lQ3w9EY6A-uHicfMakRnvy57XvE4bu6wBiHqStdDc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4&signature=IuxCY3JrnGVfuyvdXD7TeBXwqt_ySJalNm40VSMWGPQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5&signature=IWR07lI3B8VmzHlrwwxgWGyt9yw01IXkd_W9zk68K3E 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6&signature=KKG086kEMT2fu4c21ybf9ZNkddU1z07ZHPzdF0X4vNk 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and undefined quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1&signature=tgqva0giYvsn-FKsRYIO8d9Tm4iS85St8_ilDzFCoA4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2&signature=blj1DwMwrUc8ZhdT-7_uExNG5PSobt3955CpsZ01SGs 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3&signature=j5lQ3w9EY6A-uHicfMakRnvy57XvE4bu6wBiHqStdDc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4&signature=IuxCY3JrnGVfuyvdXD7TeBXwqt_ySJalNm40VSMWGPQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5&signature=IWR07lI3B8VmzHlrwwxgWGyt9yw01IXkd_W9zk68K3E 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6&signature=KKG086kEMT2fu4c21ybf9ZNkddU1z07ZHPzdF0X4vNk 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1&signature=zf8CQyXlM8escASLnzgE-Ty32cv2LCoVMiC34IxGVZQ 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=66&dpr=2&signature=YBES6qxx_Rs40YKoE4Mr9mWSZhXo3PXu1k9vR5pnNDU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=58&dpr=3&signature=aprnNDUh9GiAKb7qnBuhj--3toBX-It11b0RySvrreE 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=51&dpr=4&signature=SLtY4Sat8xnYeZpVGBTvpmWe1nJdtj1pqtX0zhvbqSA 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=45&dpr=5&signature=wGAYFVmOIoHFKRH6X-FMLbtjUYdb7O4WGROFXTF8KDM 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=40&dpr=6&signature=ZJbG5VWJcYC1tV9fcNSl6h1T5GgAg7ANSftkt7nn8-E 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=1&signature=tgqva0giYvsn-FKsRYIO8d9Tm4iS85St8_ilDzFCoA4 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2&signature=blj1DwMwrUc8ZhdT-7_uExNG5PSobt3955CpsZ01SGs 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3&signature=j5lQ3w9EY6A-uHicfMakRnvy57XvE4bu6wBiHqStdDc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4&signature=IuxCY3JrnGVfuyvdXD7TeBXwqt_ySJalNm40VSMWGPQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5&signature=IWR07lI3B8VmzHlrwwxgWGyt9yw01IXkd_W9zk68K3E 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6&signature=KKG086kEMT2fu4c21ybf9ZNkddU1z07ZHPzdF0X4vNk 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1&signature=zf8CQyXlM8escASLnzgE-Ty32cv2LCoVMiC34IxGVZQ 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=2&signature=blj1DwMwrUc8ZhdT-7_uExNG5PSobt3955CpsZ01SGs 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=3&signature=j5lQ3w9EY6A-uHicfMakRnvy57XvE4bu6wBiHqStdDc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4&signature=IuxCY3JrnGVfuyvdXD7TeBXwqt_ySJalNm40VSMWGPQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5&signature=IWR07lI3B8VmzHlrwwxgWGyt9yw01IXkd_W9zk68K3E 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6&signature=KKG086kEMT2fu4c21ybf9ZNkddU1z07ZHPzdF0X4vNk 6x'
+      )
+    })
+
+    it('returns srcset with fixed width and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&dpr=1&signature=zf8CQyXlM8escASLnzgE-Ty32cv2LCoVMiC34IxGVZQ 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=70&dpr=2&signature=UQWnjkkbdpin58NWsNI7fP9QnpVp3AOHQEEiTHFfAoQ 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=65&dpr=3&signature=fvJgZwx8p51mO_6ws36JssGTpJA2JZZf0213mePfHSw 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=4&signature=IuxCY3JrnGVfuyvdXD7TeBXwqt_ySJalNm40VSMWGPQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=5&signature=IWR07lI3B8VmzHlrwwxgWGyt9yw01IXkd_W9zk68K3E 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&dpr=6&signature=KKG086kEMT2fu4c21ybf9ZNkddU1z07ZHPzdF0X4vNk 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&quality=75&signature=djrhMfgKiQcXYPpa2JorQHj4zz-hmg1-6l6wGnX6Ovc 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&quality=61&signature=EQvDP8UcAkM6G8iaqO6FGhSZCcLRxwNVxcXq48BHQT4 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&quality=49&signature=uITEVTQ_jpkyXNtIvg67XmmKJU1g0QnG88d5pUAhe7Y 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=4&quality=40&signature=LcL5119TTi9sBdHwKX-fCbtAYst7kqqx1M7daGLr2Rg 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=1&quality=75&signature=djrhMfgKiQcXYPpa2JorQHj4zz-hmg1-6l6wGnX6Ovc 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=2&quality=70&signature=JFakWQFwObD94TqD71hf8X7HB6XhpTAkOcRGvaulxxI 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&dpr=3&quality=65&signature=zm3rzIUUvJTdfOkiENdcY8_900vB-QRNYHtBaZqiWIo 3x'
+      )
+    })
+
+    it('returns srcset with fixed height', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&signature=CosxSgq_XuY_XDYCDGZzMp0XHgQ45HWTTUNsfIWqAaI 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5&signature=jNdvuKhq8n1ptnvALUZ7pttVj--8wctjeDEHKlPPxtY 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6&signature=5b-Ojy9lICTxN3EoHsBWgOHhd_glloTtR7YHd6u43OM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and fixed dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&signature=CosxSgq_XuY_XDYCDGZzMp0XHgQ45HWTTUNsfIWqAaI 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5&signature=jNdvuKhq8n1ptnvALUZ7pttVj--8wctjeDEHKlPPxtY 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6&signature=5b-Ojy9lICTxN3EoHsBWgOHhd_glloTtR7YHd6u43OM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and null dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&signature=CosxSgq_XuY_XDYCDGZzMp0XHgQ45HWTTUNsfIWqAaI 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5&signature=jNdvuKhq8n1ptnvALUZ7pttVj--8wctjeDEHKlPPxtY 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6&signature=5b-Ojy9lICTxN3EoHsBWgOHhd_glloTtR7YHd6u43OM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and undefined dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&signature=CosxSgq_XuY_XDYCDGZzMp0XHgQ45HWTTUNsfIWqAaI 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5&signature=jNdvuKhq8n1ptnvALUZ7pttVj--8wctjeDEHKlPPxtY 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6&signature=5b-Ojy9lICTxN3EoHsBWgOHhd_glloTtR7YHd6u43OM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and range of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&signature=CosxSgq_XuY_XDYCDGZzMp0XHgQ45HWTTUNsfIWqAaI 4x'
+      )
+    })
+
+    it('returns srcset with fixed height and empty array of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&signature=CosxSgq_XuY_XDYCDGZzMp0XHgQ45HWTTUNsfIWqAaI 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=5&signature=jNdvuKhq8n1ptnvALUZ7pttVj--8wctjeDEHKlPPxtY 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=6&signature=5b-Ojy9lICTxN3EoHsBWgOHhd_glloTtR7YHd6u43OM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x')
+    })
+
+    it('returns srcset with fixed height and array of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&signature=OPRYWD06ACeu6W8YXkZ87-swVGCl9hCk7bPLh_wn6Cw 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&signature=4981fsA13f03qY95Xt9grU2ZyjVReTukEEGmEMaOyeU 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&signature=NYcE4xjRvJ3m8FCTwVbC30VNjuKuCJzY-pBwqMXvdLc 3x'
+      )
+    })
+
+    it('returns srcset with fixed height and fixed quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1&signature=gipsMEavWgTV3KTwyahYXj4f4KtIBXnfGl-Sf4K1AoU 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=2&signature=ILRBpAF4yyc3_lWihJwlvkid-6VZfHxNgZWhvh6Lhvs 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=3&signature=UXsqudgHsgSqDGAqC448V4vTRB_XL__FChpT19qhXNU 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=4&signature=Szk6Qc7wRuvv7hAQX3GrF-PGA7w7IFOFXnWG3lZRcd0 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=5&signature=W4QivDeu6jJOXWmIWihX24w3VPokgqUqQUSpCWMudVI 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=6&signature=NikOouFxX1NDIyqejGzzG8EpHKTeakKR3McjdQTNUxo 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and null quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: null })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1&signature=QCoyLuiBDl0ytX1cTW167ByM5jWzJg3ZibYPtN2g44I 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2&signature=KcIeRbexUWeBMCYVRfq8SC-lwl9JMSWFeQ7hgysQUqI 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3&signature=YXH8ZTUFX4YXOMStgoae85f82QivRXy_HB25C3NabjY 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4&signature=twl_a0CLY3-f3mPMAxeLDuIF9KGwTLoGQOE54FcJVC8 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5&signature=xgo3Obp4ju4-icy-U7wf6BKdhXHUlJyfXUPtHgODPhs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6&signature=J4DCGr3c180ftlc1YQi4f5tHPC4j9hit5HIteJefXZM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and undefined quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: undefined })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1&signature=QCoyLuiBDl0ytX1cTW167ByM5jWzJg3ZibYPtN2g44I 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2&signature=KcIeRbexUWeBMCYVRfq8SC-lwl9JMSWFeQ7hgysQUqI 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3&signature=YXH8ZTUFX4YXOMStgoae85f82QivRXy_HB25C3NabjY 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4&signature=twl_a0CLY3-f3mPMAxeLDuIF9KGwTLoGQOE54FcJVC8 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5&signature=xgo3Obp4ju4-icy-U7wf6BKdhXHUlJyfXUPtHgODPhs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6&signature=J4DCGr3c180ftlc1YQi4f5tHPC4j9hit5HIteJefXZM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1&signature=gipsMEavWgTV3KTwyahYXj4f4KtIBXnfGl-Sf4K1AoU 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=66&dpr=2&signature=aMY4Y3IoWsnGAp9nraijGlfvngHN8xvfbGavO8KHhW0 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=58&dpr=3&signature=OlTH_pLosHDjkTQ3FqPY4ZwzXY0pF8IIeoGdd_4CXjM 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=51&dpr=4&signature=FOBkytNoJVhy2x4DxHlw94bUY9pyxC6D1okODEVbznc 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=45&dpr=5&signature=ZwpZsCH8Bbt9BpkV0KKOiBeETd3_gfFy4RVlz-3lIv4 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=40&dpr=6&signature=IjuHRWBbL3VBz5mahP-RxbFeTI_IzHoNnefOzUHZIdc 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=1&signature=QCoyLuiBDl0ytX1cTW167ByM5jWzJg3ZibYPtN2g44I 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2&signature=KcIeRbexUWeBMCYVRfq8SC-lwl9JMSWFeQ7hgysQUqI 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3&signature=YXH8ZTUFX4YXOMStgoae85f82QivRXy_HB25C3NabjY 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4&signature=twl_a0CLY3-f3mPMAxeLDuIF9KGwTLoGQOE54FcJVC8 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5&signature=xgo3Obp4ju4-icy-U7wf6BKdhXHUlJyfXUPtHgODPhs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6&signature=J4DCGr3c180ftlc1YQi4f5tHPC4j9hit5HIteJefXZM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1&signature=gipsMEavWgTV3KTwyahYXj4f4KtIBXnfGl-Sf4K1AoU 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=2&signature=KcIeRbexUWeBMCYVRfq8SC-lwl9JMSWFeQ7hgysQUqI 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=3&signature=YXH8ZTUFX4YXOMStgoae85f82QivRXy_HB25C3NabjY 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4&signature=twl_a0CLY3-f3mPMAxeLDuIF9KGwTLoGQOE54FcJVC8 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5&signature=xgo3Obp4ju4-icy-U7wf6BKdhXHUlJyfXUPtHgODPhs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6&signature=J4DCGr3c180ftlc1YQi4f5tHPC4j9hit5HIteJefXZM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=75&dpr=1&signature=gipsMEavWgTV3KTwyahYXj4f4KtIBXnfGl-Sf4K1AoU 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=70&dpr=2&signature=FacmhyVpHbzVJtjokktiI2hdXHgSYHgMdsiwIlSeIp0 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=65&dpr=3&signature=s64KtZO2Lkb11qMiynGMJo7Q145JbKIxN1GFr87WExg 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=4&signature=twl_a0CLY3-f3mPMAxeLDuIF9KGwTLoGQOE54FcJVC8 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=5&signature=xgo3Obp4ju4-icy-U7wf6BKdhXHUlJyfXUPtHgODPhs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&quality=&dpr=6&signature=J4DCGr3c180ftlc1YQi4f5tHPC4j9hit5HIteJefXZM 6x'
+      )
+    })
+
+    it('returns srcset with fixed height, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&quality=75&signature=25rT2PoNIjb3dNUktp6uKyiL5TaPtKzAvBikvflXeuU 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&quality=61&signature=yIawysfrGLbT4SBOK-WUd_PGPhQMiUT32tKoLKtWTs0 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&quality=49&signature=LBnzxpLpiuN0-Q19nRIiwY5kh6sn-KOnMQKGfROhpJo 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=4&quality=40&signature=Vh9_hy6G8r7QULCF7wGWjWc062SwqaQKQuvE0UYZQBk 4x'
+      )
+    })
+
+    it('returns srcset with fixed height, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: 200, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=1&quality=75&signature=25rT2PoNIjb3dNUktp6uKyiL5TaPtKzAvBikvflXeuU 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=2&quality=70&signature=UloDZHD2ckqJSMcnXYHPHBIazvlBO13xXO81tUlOfFE 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?height=200&dpr=3&quality=65&signature=MJT1FBPv626BJwh2rdVRwliLRN1vPLrxibPcIkOaLg4 3x'
+      )
+    })
+
+    it('returns srcset with fixed width and fixed height', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&signature=IJM9kyvoH30hC2Xr0-FG9CZxYvDSy9MsZJBbs6Wm2kg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&signature=mSGPEv1SiYAFUO72DNUfMDdL4izJLHlwu1aiRGsonY4 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&signature=_M2FTPPtfAUaqOaRZXIOK-nHjJ3RbejVRz7jt5Bggw8 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&signature=jiT6foPkzDPgIfhnhh668OwFFKOb1etLBGKqdgQPzpk 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5&signature=pDmFhsCoX1YIB2QUKSTZuy0qpfiL67yLNKaZW0L7HSs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6&signature=kvgSWBz889aNkuaNJV1BjMTj8fdAcy_kjJo0q-r9QgY 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and fixed dpr', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: 2 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&signature=IJM9kyvoH30hC2Xr0-FG9CZxYvDSy9MsZJBbs6Wm2kg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&signature=mSGPEv1SiYAFUO72DNUfMDdL4izJLHlwu1aiRGsonY4 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&signature=_M2FTPPtfAUaqOaRZXIOK-nHjJ3RbejVRz7jt5Bggw8 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&signature=jiT6foPkzDPgIfhnhh668OwFFKOb1etLBGKqdgQPzpk 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5&signature=pDmFhsCoX1YIB2QUKSTZuy0qpfiL67yLNKaZW0L7HSs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6&signature=kvgSWBz889aNkuaNJV1BjMTj8fdAcy_kjJo0q-r9QgY 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and range of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: range(1, 4) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&signature=IJM9kyvoH30hC2Xr0-FG9CZxYvDSy9MsZJBbs6Wm2kg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&signature=mSGPEv1SiYAFUO72DNUfMDdL4izJLHlwu1aiRGsonY4 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&signature=_M2FTPPtfAUaqOaRZXIOK-nHjJ3RbejVRz7jt5Bggw8 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&signature=jiT6foPkzDPgIfhnhh668OwFFKOb1etLBGKqdgQPzpk 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and empty array of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&signature=IJM9kyvoH30hC2Xr0-FG9CZxYvDSy9MsZJBbs6Wm2kg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&signature=mSGPEv1SiYAFUO72DNUfMDdL4izJLHlwu1aiRGsonY4 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&signature=_M2FTPPtfAUaqOaRZXIOK-nHjJ3RbejVRz7jt5Bggw8 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&signature=jiT6foPkzDPgIfhnhh668OwFFKOb1etLBGKqdgQPzpk 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=5&signature=pDmFhsCoX1YIB2QUKSTZuy0qpfiL67yLNKaZW0L7HSs 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=6&signature=kvgSWBz889aNkuaNJV1BjMTj8fdAcy_kjJo0q-r9QgY 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of dprs of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [1] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&signature=IJM9kyvoH30hC2Xr0-FG9CZxYvDSy9MsZJBbs6Wm2kg 1x')
+    })
+
+    it('returns srcset with fixed width, fixed height and array of dprs', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [1, 2, 3] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&signature=IJM9kyvoH30hC2Xr0-FG9CZxYvDSy9MsZJBbs6Wm2kg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&signature=mSGPEv1SiYAFUO72DNUfMDdL4izJLHlwu1aiRGsonY4 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&signature=_M2FTPPtfAUaqOaRZXIOK-nHjJ3RbejVRz7jt5Bggw8 3x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and fixed quality', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, quality: 75 })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1&signature=PnadVjkFBE6kQMGUBuV-IVtHSoL8bmVEDXjvByjA4xg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=2&signature=5J3U-Gf37ruvbgNOSK8xKHggHOjGEB4EvlcXr2KUeP0 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=3&signature=7Prpr-BMsQeW_a7DoFhqXxi_1pKIu3xQaN_RzeBLbqM 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=4&signature=ptth3HdLo4xxV76BumAgl7n9kJIML7PNupQ_Ko35GQU 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=5&signature=YatBW63wHTllgGrZK8MqhQ_Jl66kBCoAWAULeew39vk 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=6&signature=wIezHaEl9OYPh5PdOVMH3it_nE2n9lg7Nhe6BPhsrnY 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1&signature=PnadVjkFBE6kQMGUBuV-IVtHSoL8bmVEDXjvByjA4xg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=66&dpr=2&signature=IWp9uUgUbhWZghziCC5N7Lct6Vp6ccRGVPvrRdm2WGE 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=58&dpr=3&signature=3WlYuqk7aJL7sWuMarFU1dYB9jiFVZRrMFsuzzJNPJ8 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=51&dpr=4&signature=lsQdhnA-9Zv6M0Wvy7zeu3QdC763e2In3Xq14RbQgwI 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=45&dpr=5&signature=ctuQrnocmmcQ597Tb4gxaNciH-pi5ZBfYzvNOSy6kNQ 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=40&dpr=6&signature=Zg0a1OhZeHCzhhzzzm_1MXqkOqMnREf_4DukDTZD8os 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=1&signature=I33EBra07-ZnKfQnF3q_qWcrZgrVjmyLaKGtYnUPt1A 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=2&signature=TutthSvWJtm9jcWHiMVgmnpJSYd9-9qrRmrJSpXp61w 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=3&signature=qS0bMn8ZmZ_c_uzAqz24U_e4e76z_VSDGZUS2RwxY-s 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4&signature=3tXfxmhvuVtfu5EVaama5ECwXCX3U9xG0DFJaCi6FbQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5&signature=RWLeQdABIup6zLvmubBZ_MHnnw70SVLwAUhDDQkMFZ0 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6&signature=5glXeaOZCVkKfFPYt6yjOFuKmKKPSmC9CRxkR8rYjFc 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1&signature=PnadVjkFBE6kQMGUBuV-IVtHSoL8bmVEDXjvByjA4xg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=2&signature=TutthSvWJtm9jcWHiMVgmnpJSYd9-9qrRmrJSpXp61w 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=3&signature=qS0bMn8ZmZ_c_uzAqz24U_e4e76z_VSDGZUS2RwxY-s 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4&signature=3tXfxmhvuVtfu5EVaama5ECwXCX3U9xG0DFJaCi6FbQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5&signature=RWLeQdABIup6zLvmubBZ_MHnnw70SVLwAUhDDQkMFZ0 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6&signature=5glXeaOZCVkKfFPYt6yjOFuKmKKPSmC9CRxkR8rYjFc 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&dpr=1&signature=PnadVjkFBE6kQMGUBuV-IVtHSoL8bmVEDXjvByjA4xg 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=70&dpr=2&signature=C-thQx7QmatepDvZuYtIPUmwGeMsDh347APm_qJpFFE 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=65&dpr=3&signature=z2J1hziiBKJ4NFyXNtQDpKqkFtoaTcUMxOGJcPSQ5Is 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=4&signature=3tXfxmhvuVtfu5EVaama5ECwXCX3U9xG0DFJaCi6FbQ 4x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=5&signature=RWLeQdABIup6zLvmubBZ_MHnnw70SVLwAUhDDQkMFZ0 5x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=&dpr=6&signature=5glXeaOZCVkKfFPYt6yjOFuKmKKPSmC9CRxkR8rYjFc 6x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height, range of dprs and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: range(1, 4), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&quality=75&signature=t6k4Dapq2m5a-DpuUsQw47tl02aBX9XCNQJ8NChYpLE 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&quality=61&signature=kHXoQWMZigQ3ck3lq5PE2oPB_-CgJvu0Siw0qZUCPqQ 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&quality=49&signature=uMu3kinh0aZWyJympL5MkyNblm3z5cqc4o3p5nvu5kk 3x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=4&quality=40&signature=EwcIR2na2b6Io4jqL-yoA4UIVmIiv6YlxiDREMfHNQI 4x'
+      )
+    })
+
+    it('returns srcset with fixed width, fixed height, array of dprs and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, dpr: [1, 2, 3], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=1&quality=75&signature=t6k4Dapq2m5a-DpuUsQw47tl02aBX9XCNQJ8NChYpLE 1x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=2&quality=70&signature=3cwCowdly2-A-bzVeygxuyspjL3FTvPYLleWxeyAeVI 2x,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&dpr=3&quality=65&signature=S2mYF1jlamW-ESRjeeasYvcPRNAvjetbatj0WPv2I0k 3x'
+      )
+    })
+
+    it('returns srcset with range of widths', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 4096) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&signature=-G7slD-ae7GdT1lx8I0-7iUMnkMTU3NcTGB8GzaiaNg 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=128&signature=2cC_ykc-pqoIK_NQOTjarDcJIgZD5mPu_AnK2cvCW3c 128w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=164&signature=25acIxwSYj7b6Xt-hAq0QTsGLt9fYfZWvGdwFbktRlI 164w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&signature=FhItrI5gSCF4MhngaaXcbmKYJXnC1S_NQG8UNaI5Sp0 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=269&signature=N151yMSgG6nke2hcBKRekHLXzaEWMdH80vgqXGhDhYQ 269w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=345&signature=g-xGt_iGA-wC3P8iui5l0kv_OF6CF5U0PcUb9F1gQ4w 345w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&signature=CXrismkxq7CuoNFF_BFURwtZyWyFGO-mf8lDyLbj4SM 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=566&signature=_AHoRlDZVA-iuK85k4SkSycBWLi19ixUqZU4O_kvExk 566w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=724&signature=YX7T2AvjD8bdrqCumvILMX_QRoD2Z4fEKQm5alPuHqo 724w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&signature=A2ihMdOHDl2hGG6MdocDKTMg6WNIjleM6BtbNCcr44A 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1188&signature=XmUJuVHFLItcXFN8X6I7p4fvBQH_JCarPBz32vjrcu0 1188w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1522&signature=npRnE8jsSy1oAvxAA8TVsvqk1jG00tO_NJWFYyS-YXs 1522w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&signature=4hi_0-BD3AwuUUONQAmieWJEsTAOFxrX1TLXKeHCLqE 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2497&signature=7SxlJMpbxkA54ceWURFwnyIv8dynrW7Hx3OkauT8zcM 2497w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3198&signature=Z-TSGIBt9U0OCLKKKbw2dMKefPj6LQeToy-9Sz6xzT8 3198w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&signature=TWdvbo0ucyOxAMxH8OI_T3WK7Ufbwwl40pWtPq7Ff78 4096w'
+      )
+    })
+
+    it('returns srcset with range of widths and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 4096), quality: range(70, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&quality=70&signature=jWu-9brjqLkPD_CK4SX9_yckyaQ8d8vf7oWzszbuW-0 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=128&quality=67&signature=yfCWjWUJKlzBxOqF5dJI0Ej0jzhIQZ9ttus_n4OTkoM 128w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=164&quality=65&signature=LqSqBqxAKS1QJ2W73nj7Oub9P0DMTA9KiGxY76o_ROk 164w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&quality=63&signature=AR2sBFCQej47qzamZvmh2o7L_UFsiD0NT9iooOlqb2M 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=269&quality=60&signature=a7er0FLZIMVT-ZrGwCYnXAxoanHhH97kurkXaQDTjBU 269w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=345&quality=58&signature=tyC1UtP1dzYtBbfWXqVA8xFSXG3dbv4EJad_YAOcZiQ 345w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&quality=56&signature=usF3QE7FGA6v8Gg-Qu3ExHOWdg3NxsFgdjiYSHPH8KI 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=566&quality=54&signature=5dQ7teZBhv0ytZZaURZbfAoY7y6mtXZA-zy_jUxOJdw 566w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=724&quality=52&signature=bdWpkErDsqG9yFFHzVtVJMpRkgS3UZFIxRWsHY1zo1g 724w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&quality=50&signature=glEum5UD25WemwFC-zHHkfggPWme6cWTigF7zkdf930 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1188&quality=48&signature=ttlEa2gosU-ZgI3zvofvZaY5dHudpZ9j7POJB_Xy5TQ 1188w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1522&quality=46&signature=azycXOjL-l_KmHrVKUAbfwVFTns0xGFUGWxm2MrDHZ8 1522w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&quality=45&signature=lkh8M7JSklT26KTAaybQcZ3rz2Woc9OF4JjlI6eZk7M 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2497&quality=43&signature=-lU_Y-yW-PCTKOa63d_zEw9oUunOHpHi_1EVvU7QEhI 2497w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3198&quality=42&signature=lYwxJOqDpjIrxFjZTTgJTcygSU5im7hvXKAZSAt2PPg 3198w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&quality=40&signature=2LpbFIpgUEeYFhyHaybrKWjub49WHuighWvesmRj4dk 4096w'
+      )
+    })
+
+    it('returns srcset with sequence of widths', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 4096, 6) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&signature=-G7slD-ae7GdT1lx8I0-7iUMnkMTU3NcTGB8GzaiaNg 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&signature=FhItrI5gSCF4MhngaaXcbmKYJXnC1S_NQG8UNaI5Sp0 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&signature=CXrismkxq7CuoNFF_BFURwtZyWyFGO-mf8lDyLbj4SM 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&signature=A2ihMdOHDl2hGG6MdocDKTMg6WNIjleM6BtbNCcr44A 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&signature=4hi_0-BD3AwuUUONQAmieWJEsTAOFxrX1TLXKeHCLqE 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&signature=TWdvbo0ucyOxAMxH8OI_T3WK7Ufbwwl40pWtPq7Ff78 4096w'
+      )
+    })
+
+    it('returns srcset with sequence of widths and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 4096, 6), quality: range(70, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&quality=70&signature=jWu-9brjqLkPD_CK4SX9_yckyaQ8d8vf7oWzszbuW-0 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=210&quality=63&signature=AR2sBFCQej47qzamZvmh2o7L_UFsiD0NT9iooOlqb2M 210w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=442&quality=56&signature=usF3QE7FGA6v8Gg-Qu3ExHOWdg3NxsFgdjiYSHPH8KI 442w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=928&quality=50&signature=glEum5UD25WemwFC-zHHkfggPWme6cWTigF7zkdf930 928w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1949&quality=45&signature=lkh8M7JSklT26KTAaybQcZ3rz2Woc9OF4JjlI6eZk7M 1949w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4096&quality=40&signature=2LpbFIpgUEeYFhyHaybrKWjub49WHuighWvesmRj4dk 4096w'
+      )
+    })
+
+    it('returns srcset with empty array of widths', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=100&signature=-G7slD-ae7GdT1lx8I0-7iUMnkMTU3NcTGB8GzaiaNg 100w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=134&signature=fHLmra9mxfjnp8E-7Cj7AZlJ43kRKLILUQ3Gawa0pxA 134w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=180&signature=omMuwPcMxKVGGnDk9sR2G6qD28uLIAldc-N9FvhwSH0 180w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=241&signature=09nboU72WGyryf9zyxMsNyBNu4PUrrGkuDlbM6shYas 241w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=324&signature=KOLqtvfSwSLUKnWY5-tvuaj-pOsBcN_WIHRTNLpJ7-Y 324w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=434&signature=48LOvc3n4CqstYfikmhT57XvKnydLRUa6qT-_IqZ0io 434w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=583&signature=IfEEELQp0__u7Ip-qzKQ2Plw70ybDOdrVeOz5jw9BOY 583w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=781&signature=p6sa4yVVce8AkuJagwLolgRD1nQUyzZsMw68KSQaVwM 781w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1048&signature=qz5KgcQRJHnCcubs9ldfGUGm1vzsvjBge17OWhykwp0 1048w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1406&signature=Kh16qduc4dixmTKuhASbspncSVHlDTd4DnsbcmfB6Mw 1406w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=1886&signature=WN-YBqlX-bhiWxFydOVBsfkVIWjIuz09qvHkA2UZWvs 1886w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=2530&signature=wH5aHb7P0S6xuJvBDoPgZPIo2-nosgViwt2ADVGhAvw 2530w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=3394&signature=e_fi5Y-uruuUWips4wxJt5WkHKETn9P1MmHXVD9Cvxs 3394w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=4553&signature=AuXvD4c7FN279MOC63ogznGAqYmHqLCVDgQvl0I1IKM 4553w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=6107&signature=nWDdC0v7d695Oo_bdhgc_AkxCkIyF7FSZgj7bAcOkNo 6107w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=8192&signature=HNmtIa6jhuc8o3Yir2zZBjDvgiiAwGeMzM-x7ow1dSE 8192w'
+      )
+    })
+
+    it('returns srcset with array of widths of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200] })
+
+      expect(srcset).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&signature=oV-jpcwoz0-UdXsZCVCecPwJ3tb88vfb1lwM2nKfq60 200w')
+    })
+
+    it('returns srcset with array of widths', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&signature=oV-jpcwoz0-UdXsZCVCecPwJ3tb88vfb1lwM2nKfq60 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&signature=BEQUozs795ZFLKcwTBrTrY3Ga0l8WeZE0cjVo_JjgwU 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&signature=eboiZiD6J2-wWKqi3aZLUiu2YQZTDeY1vxcfqmtsQhw 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and range of heights', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], height: range(300, 500) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&signature=5LR9YGho_DVBmGZ_aR5NpG-051zJG23u-LNJe3-nEwU 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=387&signature=19698XtncA9IDVyo5d60-c3HPPRDOM3nxSYbGh8sCKY 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&signature=nB5xubhzQyvrGIU1e2JtoaS5KJC76qiHwTYwTtNHzE0 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and empty array of heights', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=&signature=voipBs7wOgfiKHFeBqPi4zkBCwi_o4fNyy2eHur9Yr0 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=&signature=qtZUoqn9irWsq-35NKO1VAxqk4YaC961LroJOa8VgrA 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=&signature=LMYoRf_j_cYye718DX_kur72ZLpwlhzS1PB0ki7Bb18 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of heights of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [300] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&signature=5LR9YGho_DVBmGZ_aR5NpG-051zJG23u-LNJe3-nEwU 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=&signature=qtZUoqn9irWsq-35NKO1VAxqk4YaC961LroJOa8VgrA 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=&signature=LMYoRf_j_cYye718DX_kur72ZLpwlhzS1PB0ki7Bb18 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of heights', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [300, 400, 500] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&signature=5LR9YGho_DVBmGZ_aR5NpG-051zJG23u-LNJe3-nEwU 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=400&signature=6fgNZ57ztEH-0R6V_V8HpQnJDLs9FmmWujzZ-qz0Nl0 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&signature=nB5xubhzQyvrGIU1e2JtoaS5KJC76qiHwTYwTtNHzE0 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&signature=VxBn4eboQoUAC6C9kAoxTU88_pl8JsXIb9vna7IPEoU 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=55&signature=HTal7YeJU25OqZhnEXpJmutEJL64XjZ50QIXBlcoS9w 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=40&signature=YFxQwbC4YCEJ3tPLh5W1VsMjPa0NYNl9E-V-J2OmR2I 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and empty array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: [] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=&signature=JsmWwDAytj5PL79rbgPMxsyZKpiShrlabxnZ6PYytW4 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=&signature=o3FvvPVmG52OlZucA6qrG3ponTY3AksB8oaQU83XxLk 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=&signature=v3Idf3iopkK41AjHZb1oBXcjmf0wgjcdrr3Bpw1bkJ0 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of qualities of size 1', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: [75] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&signature=VxBn4eboQoUAC6C9kAoxTU88_pl8JsXIb9vna7IPEoU 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=&signature=o3FvvPVmG52OlZucA6qrG3ponTY3AksB8oaQU83XxLk 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=&signature=v3Idf3iopkK41AjHZb1oBXcjmf0wgjcdrr3Bpw1bkJ0 400w'
+      )
+    })
+
+    it('returns srcset with array of widths and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&quality=75&signature=VxBn4eboQoUAC6C9kAoxTU88_pl8JsXIb9vna7IPEoU 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&quality=70&signature=_Ec1jIoy0coaBnbqa3h5Uhsm3wWhJEJUszV_7swM-gA 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&quality=65&signature=n6ib7RsWbTSQvN5F5Rzy1wB9wexKx31IS-Omdg__RqY 400w'
+      )
+    })
+
+    it('returns srcset with array of widths, range of heights and range of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], height: range(300, 500), quality: range(75, 40) })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&signature=avflohh59fJI6eHUXL232Xb-wNXiraj5uxYPTFMCnNs 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=387&quality=55&signature=pvros3H2YqyZC8ae52VisbXo3OhsN4HVt90ElngutHs 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&quality=40&signature=_6g3LZxEZIcathWXeSaoIWISgz7kkUPmnP98RLp0qEM 400w'
+      )
+    })
+
+    it('returns srcset with array of widths, array of heights and array of qualities', () => {
+      const srcset = Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [200, 300, 400], height: [300, 400, 500], quality: [75, 70, 65] })
+
+      expect(srcset).toBe(
+        'https://assets.imglab-cdn.net/example.jpeg?width=200&height=300&quality=75&signature=avflohh59fJI6eHUXL232Xb-wNXiraj5uxYPTFMCnNs 200w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=300&height=400&quality=70&signature=LOLbD83Cxw8nsn4jkHu33AOJEbhB3y3EWlDTUbf3g6A 300w,\n' +
+        'https://assets.imglab-cdn.net/example.jpeg?width=400&height=500&quality=65&signature=KBMGUlSlyzUy4blPYnPh54Uu75v1lPyi4lSS_2hrkRE 400w'
+      )
+    })
+
+    it('throws a new error when width is fluid and dpr is also fluid', () => {
+       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: range(1, 3) }) }).toThrow(Error)
+       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: [1, 2, 3] }) }).toThrow(Error)
+       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+    })
+
+    it('throws a new error when width is not fluid and height is fluid', () => {
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: range(100, 300) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { height: [100, 200, 300] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 100, height: range(100, 300) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: 100, height: [100, 200, 300] }) }).toThrow(Error)
+    })
+
+    it('throws a new error when width and height are not specified and dpr is fluid', () => {
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { dpr: [1, 2, 3] }) }).toThrow(Error)
+    })
+  })
+})
diff --git a/test/srcset/utils.test.js b/test/srcset/utils.test.js
new file mode 100644
index 0000000..4473f76
--- /dev/null
+++ b/test/srcset/utils.test.js
@@ -0,0 +1,135 @@
+import Utils from '../../src/srcset/utils'
+import Range from '../../src/range'
+
+const range = Range.range
+
+describe ('Utils', () => {
+  describe('normalizeParams', () => {
+    it('returns normalized params', () => {
+      expect(Utils.normalizeParams({})).toEqual({})
+      expect(Utils.normalizeParams({ dpr: [] })).toEqual({})
+      expect(Utils.normalizeParams({ dpr: [], width: [] })).toEqual({})
+
+      expect(Utils.normalizeParams({ blur: 100, dpr: [], width: [], format: 'png' })).toEqual(
+        { blur: 100, format: 'png'}
+      )
+
+      expect(Utils.normalizeParams({ blur: 100, dpr: 1, width: 100, format: 'png'})).toEqual(
+        { blur: 100, dpr: 1, width: 100, format: 'png' }
+      )
+
+      expect(Utils.normalizeParams({ blur: 100, dpr: [1, 2, 3], width: [100, 200, 300], format: 'png' })).toEqual(
+        { blur: 100, dpr: [1, 2, 3], width: [100, 200, 300], format: 'png' }
+      )
+
+      expect(Utils.normalizeParams({ blur: 100, dpr: range(1, 3), width: range(100, 300), format: 'png' })).toEqual(
+        { blur: 100, dpr: range(1, 3), width: range(100, 300), format: 'png' }
+      )
+    })
+  })
+
+  describe('splitParamsDpr', () => {
+    it('returns split params by dpr', () => {
+      expect(Utils.splitParamsDpr({ width: 100, dpr: [1, 2], format: 'png' })).toEqual([
+        { width: 100, dpr: 1, format: 'png' },
+        { width: 100, dpr: 2, format: 'png' }
+      ])
+
+      expect(Utils.splitParamsDpr({ width: 100, dpr: [1, 2], quality: [75], format: 'png' })).toEqual([
+        { width: 100, dpr: 1, quality: 75, format: 'png' },
+        { width: 100, dpr: 2, quality: undefined, format: 'png' }
+      ])
+
+      expect(Utils.splitParamsDpr({ width: 100, dpr: [1, 2], quality: [75, 40], format: 'png' })).toEqual([
+        { width: 100, dpr: 1, quality: 75, format: 'png' },
+        { width: 100, dpr: 2, quality: 40, format: 'png' }
+      ])
+
+      expect(Utils.splitParamsDpr({ width: 100, dpr: range(1, 2), format: 'png' })).toEqual([
+        { width: 100, dpr: 1, format: 'png' },
+        { width: 100, dpr: 2, format: 'png' }
+      ])
+
+      expect(Utils.splitParamsDpr({ width: 100, dpr: range(1, 2), quality: [75], format: 'png' })).toEqual([
+        { width: 100, dpr: 1, quality: 75, format: 'png' },
+        { width: 100, dpr: 2, quality: undefined, format: 'png' }
+      ])
+
+      expect(Utils.splitParamsDpr({ width: 100, dpr: range(1, 2), quality: range(75, 40), format: 'png' })).toEqual([
+        { width: 100, dpr: 1, quality: 75, format: 'png' },
+        { width: 100, dpr: 2, quality: 40, format: 'png' }
+      ])
+    })
+
+    describe('splitParamsWidth', () => {
+      it('returns split params by width', () => {
+        expect(Utils.splitParamsWidth({ width: [100, 200], format: 'png' })).toEqual([
+          { width: 100, format: 'png' },
+          { width: 200, format: 'png' }
+        ])
+
+        expect(Utils.splitParamsWidth({ width: [100, 200], height: [300], quality: [75], format: 'png' })).toEqual([
+          { width: 100, height: 300, quality: 75, format: 'png' },
+          { width: 200, height: undefined, quality: undefined, format: 'png' }
+        ])
+
+        expect(Utils.splitParamsWidth({ width: range(100, 200), format: 'png' })).toEqual([
+          { width: 100, format: 'png' },
+          { width: 105, format: 'png' },
+          { width: 110, format: 'png' },
+          { width: 115, format: 'png' },
+          { width: 120, format: 'png' },
+          { width: 126, format: 'png' },
+          { width: 132, format: 'png' },
+          { width: 138, format: 'png' },
+          { width: 145, format: 'png' },
+          { width: 152, format: 'png' },
+          { width: 159, format: 'png' },
+          { width: 166, format: 'png' },
+          { width: 174, format: 'png' },
+          { width: 182, format: 'png' },
+          { width: 191, format: 'png' },
+          { width: 200, format: 'png' }
+        ])
+
+        expect(Utils.splitParamsWidth({ width: range(100, 200), height: [300], quality: [75], format: 'png' })).toEqual([
+          { width: 100, height: 300, quality: 75, format: 'png' },
+          { width: 105, height: undefined, quality: undefined, format: 'png' },
+          { width: 110, height: undefined, quality: undefined, format: 'png' },
+          { width: 115, height: undefined, quality: undefined, format: 'png' },
+          { width: 120, height: undefined, quality: undefined, format: 'png' },
+          { width: 126, height: undefined, quality: undefined, format: 'png' },
+          { width: 132, height: undefined, quality: undefined, format: 'png' },
+          { width: 138, height: undefined, quality: undefined, format: 'png' },
+          { width: 145, height: undefined, quality: undefined, format: 'png' },
+          { width: 152, height: undefined, quality: undefined, format: 'png' },
+          { width: 159, height: undefined, quality: undefined, format: 'png' },
+          { width: 166, height: undefined, quality: undefined, format: 'png' },
+          { width: 174, height: undefined, quality: undefined, format: 'png' },
+          { width: 182, height: undefined, quality: undefined, format: 'png' },
+          { width: 191, height: undefined, quality: undefined, format: 'png' },
+          { width: 200, height: undefined, quality: undefined, format: 'png' }
+        ])
+
+        expect(Utils.splitParamsWidth({ width: range(100, 200), height: range(300, 500), quality: range(75, 40), format: 'png' })).toEqual([
+          { width: 100, height: 300, quality: 75, format: 'png' },
+          { width: 105, height: 310, quality: 72, format: 'png' },
+          { width: 110, height: 321, quality: 69, format: 'png' },
+          { width: 115, height: 332, quality: 66, format: 'png' },
+          { width: 120, height: 344, quality: 63, format: 'png' },
+          { width: 126, height: 356, quality: 61, format: 'png' },
+          { width: 132, height: 368, quality: 58, format: 'png' },
+          { width: 138, height: 381, quality: 56, format: 'png' },
+          { width: 145, height: 394, quality: 54, format: 'png' },
+          { width: 152, height: 408, quality: 51, format: 'png' },
+          { width: 159, height: 422, quality: 49, format: 'png' },
+          { width: 166, height: 436, quality: 47, format: 'png' },
+          { width: 174, height: 451, quality: 45, format: 'png' },
+          { width: 182, height: 467, quality: 43, format: 'png' },
+          { width: 191, height: 483, quality: 42, format: 'png' },
+          { width: 200, height: 500, quality: 40, format: 'png' }
+        ])
+      })
+    })
+  })
+})
diff --git a/test/url.test.js b/test/url.test.js
index 030ebd6..daa7fda 100644
--- a/test/url.test.js
+++ b/test/url.test.js
@@ -32,6 +32,12 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
     })
 
+    it('returns url with undefined params', () => {
+      const url = Url.url('assets', 'example.jpeg', { width: 200, download: undefined })
+
+      expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
+    })
+
     it('returns url with params using string path', () => {
       const url = Url.url('assets', 'example.jpeg', { width: 200, height: 300, watermark: 'example.svg', format: 'png' })
 
@@ -238,6 +244,12 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
     })
 
+    it('returns url with undefined params', () => {
+      const url = Url.url(SOURCE, 'example.jpeg', { width: 200, download: undefined })
+
+      expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=')
+    })
+
     it('returns url with params using string path', () => {
       const url = Url.url(
         SOURCE,
@@ -484,6 +496,12 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=&signature=ljL9HNRaxVrk7jfQaf6FPYFZn4RJzQPCW-aVNJoIQI8')
     })
 
+    it('returns url with undefined params', () => {
+      const url = Url.url(SECURE_SOURCE, 'example.jpeg', { width: 200, download: undefined })
+
+      expect(url).toBe('https://assets.imglab-cdn.net/example.jpeg?width=200&download=&signature=ljL9HNRaxVrk7jfQaf6FPYFZn4RJzQPCW-aVNJoIQI8')
+    })
+
     it('returns url with params using string path', () => {
       const url = Url.url(SECURE_SOURCE, 'example.jpeg', { width: 200, height: 300, watermark: 'example.svg', format: 'png' })
 
diff --git a/test/utils.test.js b/test/url/utils.test.js
similarity index 91%
rename from test/utils.test.js
rename to test/url/utils.test.js
index 78737af..2a2aaea 100644
--- a/test/utils.test.js
+++ b/test/url/utils.test.js
@@ -1,4 +1,4 @@
-import Utils from '../src/utils'
+import Utils from '../../src/url/utils'
 
 describe('Utils', () => {
   describe('normalizePath', () => {
@@ -25,6 +25,8 @@ describe('Utils', () => {
     it('returns normalized params', () => {
       expect(Utils.normalizeParams({})).toEqual({})
       expect(Utils.normalizeParams({ width: 200, height: 300})).toEqual({ width: 200, height: 300})
+      expect(Utils.normalizeParams({ width: 200, height: 300, download: null })).toEqual({ width: 200, height: 300, download: '' })
+      expect(Utils.normalizeParams({ width: 200, height: 300, download: undefined })).toEqual({ width: 200, height: 300, download: '' })
       expect(Utils.normalizeParams({ trim: 'color', 'trim-color': 'orange' })).toEqual({ trim: 'color', 'trim-color': 'orange' })
       expect(Utils.normalizeParams({ trim: 'color', trim_color: 'orange' })).toEqual({ trim: 'color', 'trim-color': 'orange' })
       expect(Utils.normalizeParams({ trim: 'color', trimColor: 'orange' })).toEqual({ trim: 'color', 'trim-color': 'orange' })

From 4acbc9d7d634c142dca8ed541d411410844d9269 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Wed, 11 Jan 2023 18:13:28 +0100
Subject: [PATCH 08/15] Upgrade caniuse-lite

---
 package-lock.json | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 27506ec..2bf2f3f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2899,14 +2899,20 @@
       }
     },
     "node_modules/caniuse-lite": {
-      "version": "1.0.30001283",
-      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001283.tgz",
-      "integrity": "sha512-9RoKo841j1GQFSJz/nCXOj0sD7tHBtlowjYlrqIUS812x9/emfBLBt6IyMz1zIaYc/eRL8Cs6HPUVi2Hzq4sIg==",
-      "dev": true,
-      "funding": {
-        "type": "opencollective",
-        "url": "https://opencollective.com/browserslist"
-      }
+      "version": "1.0.30001442",
+      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001442.tgz",
+      "integrity": "sha512-239m03Pqy0hwxYPYR5JwOIxRJfLTWtle9FV8zosfV5pHg+/51uD4nxcUlM8+mWWGfwKtt8lJNHnD3cWw9VZ6ow==",
+      "dev": true,
+      "funding": [
+        {
+          "type": "opencollective",
+          "url": "https://opencollective.com/browserslist"
+        },
+        {
+          "type": "tidelift",
+          "url": "https://tidelift.com/funding/github/npm/caniuse-lite"
+        }
+      ]
     },
     "node_modules/chalk": {
       "version": "2.4.2",
@@ -9181,9 +9187,9 @@
       "dev": true
     },
     "caniuse-lite": {
-      "version": "1.0.30001283",
-      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001283.tgz",
-      "integrity": "sha512-9RoKo841j1GQFSJz/nCXOj0sD7tHBtlowjYlrqIUS812x9/emfBLBt6IyMz1zIaYc/eRL8Cs6HPUVi2Hzq4sIg==",
+      "version": "1.0.30001442",
+      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001442.tgz",
+      "integrity": "sha512-239m03Pqy0hwxYPYR5JwOIxRJfLTWtle9FV8zosfV5pHg+/51uD4nxcUlM8+mWWGfwKtt8lJNHnD3cWw9VZ6ow==",
       "dev": true
     },
     "chalk": {

From c675a7310cc11e75a242847166f1f65bdb59b5a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Thu, 12 Jan 2023 12:10:13 +0100
Subject: [PATCH 09/15] Linting code with ESLint

---
 src/color.js              |  6 +++---
 src/position.js           |  8 ++++----
 src/range.js              | 12 ++++++------
 src/sequence.js           |  2 +-
 src/signature.js          |  2 +-
 src/source.js             | 22 +++++++++++-----------
 src/srcset.js             | 16 ++++++++--------
 src/srcset/utils.js       | 30 +++++++++++++++---------------
 src/url.js                | 18 +++++++++---------
 src/url/utils.js          | 12 ++++++------
 test/source.test.js       |  4 ++--
 test/srcset.test.js       | 12 ++++++------
 test/srcset/utils.test.js |  6 +++---
 test/url.test.js          |  4 ++--
 test/url/utils.test.js    |  4 ++--
 15 files changed, 79 insertions(+), 79 deletions(-)

diff --git a/src/color.js b/src/color.js
index feb6b06..d2d3656 100644
--- a/src/color.js
+++ b/src/color.js
@@ -150,7 +150,7 @@ export default class Color {
     'yellowgreen'
   ]
 
-  static color() {
+  static color () {
     if (arguments.length === 1 && Color.#COLORS.includes(arguments[0])) {
       return arguments[0]
     }
@@ -166,11 +166,11 @@ export default class Color {
     throw new Error('Invalid color')
   }
 
-  static #areValidComponents() {
+  static #areValidComponents () {
     return [...arguments].every((component) => { return Color.#isValidComponent(component) })
   }
 
-  static #isValidComponent(component) {
+  static #isValidComponent (component) {
     return Number.isInteger(component) && component >= 0 && component <= 255
   }
 }
diff --git a/src/position.js b/src/position.js
index 0433c57..d01572a 100644
--- a/src/position.js
+++ b/src/position.js
@@ -2,7 +2,7 @@ export default class Position {
   static #HORIZONTAL = ['left', 'center', 'right']
   static #VERTICAL = ['top', 'middle', 'bottom']
 
-  static position() {
+  static position () {
     if (arguments.length === 1 && Position.#isValidPosition(arguments[0])) {
       return arguments[0]
     }
@@ -14,7 +14,7 @@ export default class Position {
     throw new Error('Invalid position')
   }
 
-  static #isValidPosition() {
+  static #isValidPosition () {
     if (arguments.length === 1 && Position.#isValidDirection(arguments[0])) {
       return true
     }
@@ -26,11 +26,11 @@ export default class Position {
     return false
   }
 
-  static #isValidDirection(direction) {
+  static #isValidDirection (direction) {
     return Position.#HORIZONTAL.includes(direction) || Position.#VERTICAL.includes(direction)
   }
 
-  static #areValidDirections(directionA, directionB) {
+  static #areValidDirections (directionA, directionB) {
     return (Position.#HORIZONTAL.includes(directionA) && Position.#VERTICAL.includes(directionB)) ||
     (Position.#HORIZONTAL.includes(directionB) && Position.#VERTICAL.includes(directionA))
   }
diff --git a/src/range.js b/src/range.js
index be49c9c..8d6f618 100644
--- a/src/range.js
+++ b/src/range.js
@@ -3,29 +3,29 @@ export default class Range {
   #last
   #length
 
-  static range(first, last) {
+  static range (first, last) {
     return new Range(first, last)
   }
 
-  constructor(first, last) {
+  constructor (first, last) {
     this.#first = first
     this.#last = last
     this.#length = Math.abs(this.last - this.first) + 1
   }
 
-  get first() {
+  get first () {
     return this.#first
   }
 
-  get last() {
+  get last () {
     return this.#last
   }
 
-  get length() {
+  get length () {
     return this.#length
   }
 
-  toArray() {
+  toArray () {
     const inc = this.first < this.last ? 1 : -1
 
     return Array.from({ length: this.length }, (_, i) => this.first + (i * inc))
diff --git a/src/sequence.js b/src/sequence.js
index 9ef0467..d363d87 100644
--- a/src/sequence.js
+++ b/src/sequence.js
@@ -1,7 +1,7 @@
 export default class Sequence {
   static DEFAULT_SIZE = 16
 
-  static sequence(first, last, size = Sequence.DEFAULT_SIZE) {
+  static sequence (first, last, size = Sequence.DEFAULT_SIZE) {
     if (size <= 0) return []
     if (size === 1) return [first]
     if (size === 2) return [first, last]
diff --git a/src/signature.js b/src/signature.js
index 87430bc..e0d0dea 100644
--- a/src/signature.js
+++ b/src/signature.js
@@ -1,7 +1,7 @@
 import crypto from 'crypto'
 
 export default class Signature {
-  static generate(source, path, encodedParams = null) {
+  static generate (source, path, encodedParams = null) {
     const decodedSecureKey = Buffer.from(source.secureKey, 'base64')
     const decodedSecureSalt = Buffer.from(source.secureSalt, 'base64')
     const hmac = crypto.createHmac('sha256', decodedSecureKey)
diff --git a/src/source.js b/src/source.js
index eba8e85..b7a9087 100644
--- a/src/source.js
+++ b/src/source.js
@@ -11,7 +11,7 @@ export default class Source {
   #secureSalt
   #subdomains
 
-  constructor(name, opts = {}) {
+  constructor (name, opts = {}) {
     opts = { ...Source.#DEFAULT_OPTS, ...opts }
 
     this.#host = opts.host
@@ -23,43 +23,43 @@ export default class Source {
     this.#subdomains = opts.subdomains
   }
 
-  get host() {
+  get host () {
     return (this.#subdomains ? `${this.#name}.${this.#host}` : this.#host)
   }
 
-  get https() {
+  get https () {
     return this.#https
   }
 
-  get name() {
+  get name () {
     return this.#name
   }
 
-  get port() {
+  get port () {
     return this.#port
   }
 
-  get secureKey() {
+  get secureKey () {
     return this.#secureKey
   }
 
-  get secureSalt() {
+  get secureSalt () {
     return this.#secureSalt
   }
 
-  get subdomains() {
+  get subdomains () {
     return this.#subdomains
   }
 
-  scheme() {
+  scheme () {
     return (this.#https ? 'https' : 'http')
   }
 
-  path(path) {
+  path (path) {
     return (this.#subdomains ? path : _path.join(this.#name, path))
   }
 
-  isSecure() {
+  isSecure () {
     return !!(this.#secureKey && this.#secureSalt)
   }
 }
diff --git a/src/srcset.js b/src/srcset.js
index 5dc162b..0f46eb8 100644
--- a/src/srcset.js
+++ b/src/srcset.js
@@ -7,10 +7,10 @@ export default class Srcset {
   static #DEFAULT_DPRS = [1, 2, 3, 4, 5, 6]
   static #DEFAULT_WIDTHS = Sequence.sequence(100, 8192)
 
-  static srcset(source, path, params = {}) {
+  static srcset (source, path, params = {}) {
     params = Utils.normalizeParams(params)
 
-    switch(true) {
+    switch (true) {
       case Srcset.#isFluid(params.width):
         if (Srcset.#isFluid(params.dpr)) {
           throw new Error('dpr as Array or Range is not allowed when width is also an Array or Range')
@@ -22,17 +22,17 @@ export default class Srcset {
           throw new Error('height as Array or Range is only allowed when width is also an Array or Range')
         }
 
-        return Srcset.#srcset_dpr(source, path, {...params, ...{dpr: Srcset.#dprs(params)}})
+        return Srcset.#srcset_dpr(source, path, { ...params, ...{ dpr: Srcset.#dprs(params) } })
       default:
         if (Srcset.#isFluid(params.dpr)) {
           throw new Error('dpr as Array or Range is not allowed without specifying width or height')
         }
 
-        return Srcset.#srcset_width(source, path, {...params, ...{width: Srcset.#DEFAULT_WIDTHS}})
+        return Srcset.#srcset_width(source, path, { ...params, ...{ width: Srcset.#DEFAULT_WIDTHS } })
     }
   }
 
-  static #dprs(params) {
+  static #dprs (params) {
     if (Srcset.#isFluid(params.dpr)) {
       return params.dpr
     } else {
@@ -40,17 +40,17 @@ export default class Srcset {
     }
   }
 
-  static #isFluid(value) {
+  static #isFluid (value) {
     return Array.isArray(value) || value instanceof Range
   }
 
-  static #srcset_dpr(source, path, params) {
+  static #srcset_dpr (source, path, params) {
     return Utils.splitParamsDpr(params).map(
       (splitParams) => `${Url.url(source, path, splitParams)} ${splitParams.dpr}x`
     ).join(',\n')
   }
 
-  static #srcset_width(source, path, params) {
+  static #srcset_width (source, path, params) {
     return Utils.splitParamsWidth(params).map(
       (splitParams) => `${Url.url(source, path, splitParams)} ${splitParams.width}w`
     ).join(',\n')
diff --git a/src/srcset/utils.js b/src/srcset/utils.js
index 71812a9..2cd9457 100644
--- a/src/srcset/utils.js
+++ b/src/srcset/utils.js
@@ -7,26 +7,26 @@ export default class Utils {
   static #SPLIT_DPR_KEYS = ['dpr', 'quality']
   static #SPLIT_WIDTH_KEYS = ['width', 'height', 'quality']
 
-  static normalizeParams(params) {
+  static normalizeParams (params) {
     return Object.entries(params).reduce((normalizedParams, [key, value]) => {
       return Object.assign(normalizedParams, Utils.#normalizeParam(key, value))
     }, {})
   }
 
-  static splitParamsDpr(params) {
+  static splitParamsDpr (params) {
     return Utils.#splitValues(params, Utils.#SPLIT_DPR_KEYS, params.dpr.length).map(
-      ([dpr, quality]) => Utils.#mergeParams(params, {dpr: dpr, quality: quality})
+      ([dpr, quality]) => Utils.#mergeParams(params, { dpr, quality })
     )
   }
 
-  static splitParamsWidth(params) {
+  static splitParamsWidth (params) {
     return Utils.#splitValues(params, Utils.#SPLIT_WIDTH_KEYS, Utils.#splitSize(params.width)).map(
-      ([width, height, quality]) => Utils.#mergeParams(params, {width: width, height: height, quality: quality})
+      ([width, height, quality]) => Utils.#mergeParams(params, { width, height, quality })
     )
   }
 
-  static #normalizeParam(key, value) {
-    switch(true) {
+  static #normalizeParam (key, value) {
+    switch (true) {
       case Utils.#NORMALIZE_KEYS.includes(key) && Array.isArray(value) && value.length === 0:
         return {}
       default:
@@ -34,8 +34,8 @@ export default class Utils {
     }
   }
 
-  static #splitSize(value) {
-    switch(true) {
+  static #splitSize (value) {
+    switch (true) {
       case value instanceof Range:
         return Sequence.DEFAULT_SIZE
       default:
@@ -43,12 +43,12 @@ export default class Utils {
     }
   }
 
-  static #splitValues(params, keys, size) {
+  static #splitValues (params, keys, size) {
     return Utils.#zip(keys.map((key) => Utils.#splitValue(key, params[key], size)))
   }
 
-  static #splitValue(key, value, size) {
-    switch(true) {
+  static #splitValue (key, value, size) {
+    switch (true) {
       case key === 'dpr' && value instanceof Range:
         return value.toArray()
       case value instanceof Range:
@@ -60,13 +60,13 @@ export default class Utils {
     }
   }
 
-  static #zip(arrays) {
+  static #zip (arrays) {
     const length = Math.max(...arrays.map(array => array.length))
 
-    return Array.from({ length: length }, (_, i) => arrays.map(array => array[i]))
+    return Array.from({ length }, (_, i) => arrays.map(array => array[i]))
   }
 
-  static #mergeParams(params, mergeParams) {
+  static #mergeParams (params, mergeParams) {
     return {
       ...params,
       ...Object.fromEntries(
diff --git a/src/url.js b/src/url.js
index dc9a345..000786e 100644
--- a/src/url.js
+++ b/src/url.js
@@ -3,7 +3,7 @@ import Signature from './signature'
 import Utils from './url/utils'
 
 export default class Url {
-  static url(source, path, params = {}) {
+  static url (source, path, params = {}) {
     if (typeof source === 'string') {
       return Url.#urlForSource(new Source(source), path, params)
     }
@@ -15,11 +15,11 @@ export default class Url {
     throw new Error('Invalid source name or source')
   }
 
-  static #urlForSource(source, path, params) {
-    var normalizedPath = Utils.normalizePath(path)
-    var normalizedParams = Utils.normalizeParams(params)
+  static #urlForSource (source, path, params) {
+    const normalizedPath = Utils.normalizePath(path)
+    const normalizedParams = Utils.normalizeParams(params)
 
-    var url = new URL('https://imglab-cdn.net')
+    const url = new URL('https://imglab-cdn.net')
 
     url.protocol = source.scheme()
     url.hostname = source.host
@@ -30,7 +30,7 @@ export default class Url {
     return url.toString()
   }
 
-  static #encodePath(path) {
+  static #encodePath (path) {
     if (Utils.isWebURL(path)) {
       return encodeURIComponent(path)
     } else {
@@ -40,13 +40,13 @@ export default class Url {
     }
   }
 
-  static #encodeParams(source, path, params) {
+  static #encodeParams (source, path, params) {
     if (Object.keys(params).length === 0) {
       return Url.#encodeEmptyParams(source, path)
     }
 
     if (source.isSecure()) {
-      params['signature'] = Signature.generate(source, path, new URLSearchParams(params).toString())
+      params.signature = Signature.generate(source, path, new URLSearchParams(params).toString())
 
       return new URLSearchParams(params)
     } else {
@@ -54,7 +54,7 @@ export default class Url {
     }
   }
 
-  static #encodeEmptyParams(source, path) {
+  static #encodeEmptyParams (source, path) {
     if (source.isSecure()) {
       return new URLSearchParams({ signature: Signature.generate(source, path) })
     } else {
diff --git a/src/url/utils.js b/src/url/utils.js
index 5b86ed6..7555849 100644
--- a/src/url/utils.js
+++ b/src/url/utils.js
@@ -5,17 +5,17 @@ export default class Utils {
 
   static #WEB_URL_PROTOCOLS = ['https:', 'http:']
 
-  static normalizePath(path) {
+  static normalizePath (path) {
     return path.replace(Utils.#NORMALIZE_PATH_PREFIX_REGEXP, '').replace(Utils.#NORMALIZE_PATH_SUFFIX_REGEXP, '')
   }
 
-  static normalizeParams(params) {
+  static normalizeParams (params) {
     return Object.entries(params).reduce((normalizedParams, [key, value]) => {
       return Object.assign(normalizedParams, Utils.#normalizeParam(Utils.#normalizeKey(key), value))
     }, {})
   }
 
-  static isWebURL(url) {
+  static isWebURL (url) {
     try {
       const parsedURL = new URL(url)
 
@@ -25,12 +25,12 @@ export default class Utils {
     }
   }
 
-  static #normalizeKey(key) {
+  static #normalizeKey (key) {
     return key.replace(Utils.#NORMALIZE_KEY_REGEXP, '$1-$2').replace('_', '-').toLowerCase()
   }
 
-  static #normalizeParam(key, value) {
-    switch(true) {
+  static #normalizeParam (key, value) {
+    switch (true) {
       case key === 'expires' && value instanceof Date:
         return { [key]: Math.floor(value / 1000) }
       case value === undefined || value === null:
diff --git a/test/source.test.js b/test/source.test.js
index 24d750f..7829bca 100644
--- a/test/source.test.js
+++ b/test/source.test.js
@@ -60,13 +60,13 @@ describe('Source', () => {
   describe('scheme', () => {
     expect(new Source('assets').scheme()).toBe('https')
     expect(new Source('assets', { https: true }).scheme()).toBe('https')
-    expect(new Source('assets', { https: false}).scheme()).toBe('http')
+    expect(new Source('assets', { https: false }).scheme()).toBe('http')
   })
 
   describe('host', () => {
     expect(new Source('assets').host).toBe('assets.imglab-cdn.net')
     expect(new Source('assets', { subdomains: false }).host).toBe('imglab-cdn.net')
-    expect(new Source('assets', { subdomains: false, host: 'imglab.net'}).host).toBe('imglab.net')
+    expect(new Source('assets', { subdomains: false, host: 'imglab.net' }).host).toBe('imglab.net')
     expect(new Source('assets', { subdomains: true }).host).toBe('assets.imglab-cdn.net')
     expect(new Source('assets', { subdomains: true, host: 'imglab.net' }).host).toBe('assets.imglab.net')
   })
diff --git a/test/srcset.test.js b/test/srcset.test.js
index d17d49d..06f1752 100644
--- a/test/srcset.test.js
+++ b/test/srcset.test.js
@@ -3271,12 +3271,12 @@ describe('Srcset', () => {
     })
 
     it('throws a new error when width is fluid and dpr is also fluid', () => {
-       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
-       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
-       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: range(1, 3) }) }).toThrow(Error)
-       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: [1, 2, 3] }) }).toThrow(Error)
-       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
-       expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: range(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: [100, 200, 300], dpr: [1, 2, 3] }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: range(1, 3) }) }).toThrow(Error)
+      expect(() => { Srcset.srcset(SECURE_SOURCE, 'example.jpeg', { width: sequence(100, 300), dpr: [1, 2, 3] }) }).toThrow(Error)
     })
 
     it('throws a new error when width is not fluid and height is fluid', () => {
diff --git a/test/srcset/utils.test.js b/test/srcset/utils.test.js
index 4473f76..04510eb 100644
--- a/test/srcset/utils.test.js
+++ b/test/srcset/utils.test.js
@@ -3,7 +3,7 @@ import Range from '../../src/range'
 
 const range = Range.range
 
-describe ('Utils', () => {
+describe('Utils', () => {
   describe('normalizeParams', () => {
     it('returns normalized params', () => {
       expect(Utils.normalizeParams({})).toEqual({})
@@ -11,10 +11,10 @@ describe ('Utils', () => {
       expect(Utils.normalizeParams({ dpr: [], width: [] })).toEqual({})
 
       expect(Utils.normalizeParams({ blur: 100, dpr: [], width: [], format: 'png' })).toEqual(
-        { blur: 100, format: 'png'}
+        { blur: 100, format: 'png' }
       )
 
-      expect(Utils.normalizeParams({ blur: 100, dpr: 1, width: 100, format: 'png'})).toEqual(
+      expect(Utils.normalizeParams({ blur: 100, dpr: 1, width: 100, format: 'png' })).toEqual(
         { blur: 100, dpr: 1, width: 100, format: 'png' }
       )
 
diff --git a/test/url.test.js b/test/url.test.js
index daa7fda..ee2e896 100644
--- a/test/url.test.js
+++ b/test/url.test.js
@@ -189,7 +189,7 @@ describe('Url', () => {
     })
 
     it('returns url with subfolder path starting and ending with slash', () => {
-      const url = Url.url('assets', '/subfolder/example.jpeg/', { width: 200, height: 300, format: 'png'})
+      const url = Url.url('assets', '/subfolder/example.jpeg/', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/subfolder/example.jpeg?width=200&height=300&format=png')
     })
@@ -212,7 +212,7 @@ describe('Url', () => {
       expect(url).toBe('https://assets.imglab-cdn.net/http%3A%2F%2Fassets.com%2Fsubfolder%2Fexample%252C01%252C02.jpeg?width=200&height=300&format=png')
     })
 
-    it('returns url with path using a https url', () =>  {
+    it('returns url with path using a https url', () => {
       const url = Url.url('assets', 'https://assets.com/subfolder/example.jpeg', { width: 200, height: 300, format: 'png' })
 
       expect(url).toBe('https://assets.imglab-cdn.net/https%3A%2F%2Fassets.com%2Fsubfolder%2Fexample.jpeg?width=200&height=300&format=png')
diff --git a/test/url/utils.test.js b/test/url/utils.test.js
index 2a2aaea..65328c1 100644
--- a/test/url/utils.test.js
+++ b/test/url/utils.test.js
@@ -24,7 +24,7 @@ describe('Utils', () => {
   describe('normalizeParams', () => {
     it('returns normalized params', () => {
       expect(Utils.normalizeParams({})).toEqual({})
-      expect(Utils.normalizeParams({ width: 200, height: 300})).toEqual({ width: 200, height: 300})
+      expect(Utils.normalizeParams({ width: 200, height: 300 })).toEqual({ width: 200, height: 300 })
       expect(Utils.normalizeParams({ width: 200, height: 300, download: null })).toEqual({ width: 200, height: 300, download: '' })
       expect(Utils.normalizeParams({ width: 200, height: 300, download: undefined })).toEqual({ width: 200, height: 300, download: '' })
       expect(Utils.normalizeParams({ trim: 'color', 'trim-color': 'orange' })).toEqual({ trim: 'color', 'trim-color': 'orange' })
@@ -32,7 +32,7 @@ describe('Utils', () => {
       expect(Utils.normalizeParams({ trim: 'color', trimColor: 'orange' })).toEqual({ trim: 'color', 'trim-color': 'orange' })
       expect(Utils.normalizeParams({ width: 200, expires: 1464096368 })).toEqual({ width: 200, expires: 1464096368 })
       expect(Utils.normalizeParams({ width: 200, expires: '1464096368' })).toEqual({ width: 200, expires: '1464096368' })
-      expect(Utils.normalizeParams({ width: 200, expires: new Date(1464096368 * 1000)})).toEqual({ width: 200, expires: 1464096368 })
+      expect(Utils.normalizeParams({ width: 200, expires: new Date(1464096368 * 1000) })).toEqual({ width: 200, expires: 1464096368 })
     })
   })
 

From 4e3734b1c061cb472be1d428849dcacd2dc54a86 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Thu, 12 Jan 2023 12:13:06 +0100
Subject: [PATCH 10/15] Fix dependency vulnerabilities

---
 package-lock.json | 194 +++++++++++++++++++++++++++++++---------------
 1 file changed, 130 insertions(+), 64 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 2bf2f3f..0bcfaae 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2260,6 +2260,64 @@
         "node": ">=8"
       }
     },
+    "node_modules/@jridgewell/gen-mapping": {
+      "version": "0.3.2",
+      "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.2.tgz",
+      "integrity": "sha512-mh65xKQAzI6iBcFzwv28KVWSmCkdRBWoOh+bYQGW3+6OZvbbN3TqMGo5hqYxQniRcH9F2VZIoJCm4pa3BPDK/A==",
+      "dev": true,
+      "dependencies": {
+        "@jridgewell/set-array": "^1.0.1",
+        "@jridgewell/sourcemap-codec": "^1.4.10",
+        "@jridgewell/trace-mapping": "^0.3.9"
+      },
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
+    "node_modules/@jridgewell/resolve-uri": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/@jridgewell/resolve-uri/-/resolve-uri-3.1.0.tgz",
+      "integrity": "sha512-F2msla3tad+Mfht5cJq7LSXcdudKTWCVYUgw6pLFOOHSTtZlj6SWNYAp+AhuqLmWdBO2X5hPrLcu8cVP8fy28w==",
+      "dev": true,
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
+    "node_modules/@jridgewell/set-array": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/@jridgewell/set-array/-/set-array-1.1.2.tgz",
+      "integrity": "sha512-xnkseuNADM0gt2bs+BvhO0p78Mk762YnZdsuzFV018NoG1Sj1SCQvpSqa7XUaTam5vAGasABV9qXASMKnFMwMw==",
+      "dev": true,
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
+    "node_modules/@jridgewell/source-map": {
+      "version": "0.3.2",
+      "resolved": "https://registry.npmjs.org/@jridgewell/source-map/-/source-map-0.3.2.tgz",
+      "integrity": "sha512-m7O9o2uR8k2ObDysZYzdfhb08VuEml5oWGiosa1VdaPZ/A6QyPkAJuwN0Q1lhULOf6B7MtQmHENS743hWtCrgw==",
+      "dev": true,
+      "dependencies": {
+        "@jridgewell/gen-mapping": "^0.3.0",
+        "@jridgewell/trace-mapping": "^0.3.9"
+      }
+    },
+    "node_modules/@jridgewell/sourcemap-codec": {
+      "version": "1.4.14",
+      "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.4.14.tgz",
+      "integrity": "sha512-XPSJHWmi394fuUuzDnGz1wiKqWfo1yXecHQMRf2l6hztTO+nPru658AyDngaBe7isIxEkRsPR3FZh+s7iVa4Uw==",
+      "dev": true
+    },
+    "node_modules/@jridgewell/trace-mapping": {
+      "version": "0.3.17",
+      "resolved": "https://registry.npmjs.org/@jridgewell/trace-mapping/-/trace-mapping-0.3.17.tgz",
+      "integrity": "sha512-MCNzAp77qzKca9+W/+I0+sEpaUnZoeasnghNeVc41VZCEKaCH73Vq3BZZ/SzWIgrqE4H4ceI+p+b6C0mHf9T4g==",
+      "dev": true,
+      "dependencies": {
+        "@jridgewell/resolve-uri": "3.1.0",
+        "@jridgewell/sourcemap-codec": "1.4.14"
+      }
+    },
     "node_modules/@rollup/plugin-babel": {
       "version": "5.3.0",
       "resolved": "https://registry.npmjs.org/@rollup/plugin-babel/-/plugin-babel-5.3.0.tgz",
@@ -5625,13 +5683,10 @@
       }
     },
     "node_modules/json5": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/json5/-/json5-2.2.0.tgz",
-      "integrity": "sha512-f+8cldu7X/y7RAJurMEJmdoKXGB/X550w2Nr3tTbezL6RwEE/iMcm+tZnXeoZtKuOq6ft8+CqzEkrIgx1fPoQA==",
+      "version": "2.2.3",
+      "resolved": "https://registry.npmjs.org/json5/-/json5-2.2.3.tgz",
+      "integrity": "sha512-XmOWe7eyHYH14cLdVPoyg+GOH3rYX++KpzrylJwSW98t3Nk+U8XOl8FWKOgwtzdb8lXGf6zYwDUzeHMWfxasyg==",
       "dev": true,
-      "dependencies": {
-        "minimist": "^1.2.5"
-      },
       "bin": {
         "json5": "lib/cli.js"
       },
@@ -5789,9 +5844,9 @@
       }
     },
     "node_modules/minimatch": {
-      "version": "3.0.4",
-      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
-      "integrity": "sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==",
+      "version": "3.1.2",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.2.tgz",
+      "integrity": "sha512-J7p63hRiAjw1NDEww1W7i37+ByIrOWO5XQQAzZ3VOcL0PNybwpfmV/N05zFAzwQ9USyEcX6t3UO+K5aqBQOIHw==",
       "dev": true,
       "dependencies": {
         "brace-expansion": "^1.1.7"
@@ -5800,12 +5855,6 @@
         "node": "*"
       }
     },
-    "node_modules/minimist": {
-      "version": "1.2.6",
-      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.6.tgz",
-      "integrity": "sha512-Jsjnk4bw3YJqYzbdyBiNsPWHPfO++UGG749Cxs6peCu5Xg4nrena6OVxOYxrQTqww0Jmwt+Ref8rggumkTLz9Q==",
-      "dev": true
-    },
     "node_modules/ms": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
@@ -6619,13 +6668,14 @@
       }
     },
     "node_modules/terser": {
-      "version": "5.10.0",
-      "resolved": "https://registry.npmjs.org/terser/-/terser-5.10.0.tgz",
-      "integrity": "sha512-AMmF99DMfEDiRJfxfY5jj5wNH/bYO09cniSqhfoyxc8sFoYIgkJy86G04UoZU5VjlpnplVu0K6Tx6E9b5+DlHA==",
+      "version": "5.16.1",
+      "resolved": "https://registry.npmjs.org/terser/-/terser-5.16.1.tgz",
+      "integrity": "sha512-xvQfyfA1ayT0qdK47zskQgRZeWLoOQ8JQ6mIgRGVNwZKdQMU+5FkCBjmv4QjcrTzyZquRw2FVtlJSRUmMKQslw==",
       "dev": true,
       "dependencies": {
+        "@jridgewell/source-map": "^0.3.2",
+        "acorn": "^8.5.0",
         "commander": "^2.20.0",
-        "source-map": "~0.7.2",
         "source-map-support": "~0.5.20"
       },
       "bin": {
@@ -6633,23 +6683,6 @@
       },
       "engines": {
         "node": ">=10"
-      },
-      "peerDependencies": {
-        "acorn": "^8.5.0"
-      },
-      "peerDependenciesMeta": {
-        "acorn": {
-          "optional": true
-        }
-      }
-    },
-    "node_modules/terser/node_modules/source-map": {
-      "version": "0.7.3",
-      "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.7.3.tgz",
-      "integrity": "sha512-CkCj6giN3S+n9qrYiBTX5gystlENnRW5jZeNLHpe6aue+SrHcG5VYwujhW9s4dY31mEGsxBDrHR6oI69fTXsaQ==",
-      "dev": true,
-      "engines": {
-        "node": ">= 8"
       }
     },
     "node_modules/test-exclude": {
@@ -8673,6 +8706,55 @@
         }
       }
     },
+    "@jridgewell/gen-mapping": {
+      "version": "0.3.2",
+      "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.2.tgz",
+      "integrity": "sha512-mh65xKQAzI6iBcFzwv28KVWSmCkdRBWoOh+bYQGW3+6OZvbbN3TqMGo5hqYxQniRcH9F2VZIoJCm4pa3BPDK/A==",
+      "dev": true,
+      "requires": {
+        "@jridgewell/set-array": "^1.0.1",
+        "@jridgewell/sourcemap-codec": "^1.4.10",
+        "@jridgewell/trace-mapping": "^0.3.9"
+      }
+    },
+    "@jridgewell/resolve-uri": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/@jridgewell/resolve-uri/-/resolve-uri-3.1.0.tgz",
+      "integrity": "sha512-F2msla3tad+Mfht5cJq7LSXcdudKTWCVYUgw6pLFOOHSTtZlj6SWNYAp+AhuqLmWdBO2X5hPrLcu8cVP8fy28w==",
+      "dev": true
+    },
+    "@jridgewell/set-array": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/@jridgewell/set-array/-/set-array-1.1.2.tgz",
+      "integrity": "sha512-xnkseuNADM0gt2bs+BvhO0p78Mk762YnZdsuzFV018NoG1Sj1SCQvpSqa7XUaTam5vAGasABV9qXASMKnFMwMw==",
+      "dev": true
+    },
+    "@jridgewell/source-map": {
+      "version": "0.3.2",
+      "resolved": "https://registry.npmjs.org/@jridgewell/source-map/-/source-map-0.3.2.tgz",
+      "integrity": "sha512-m7O9o2uR8k2ObDysZYzdfhb08VuEml5oWGiosa1VdaPZ/A6QyPkAJuwN0Q1lhULOf6B7MtQmHENS743hWtCrgw==",
+      "dev": true,
+      "requires": {
+        "@jridgewell/gen-mapping": "^0.3.0",
+        "@jridgewell/trace-mapping": "^0.3.9"
+      }
+    },
+    "@jridgewell/sourcemap-codec": {
+      "version": "1.4.14",
+      "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.4.14.tgz",
+      "integrity": "sha512-XPSJHWmi394fuUuzDnGz1wiKqWfo1yXecHQMRf2l6hztTO+nPru658AyDngaBe7isIxEkRsPR3FZh+s7iVa4Uw==",
+      "dev": true
+    },
+    "@jridgewell/trace-mapping": {
+      "version": "0.3.17",
+      "resolved": "https://registry.npmjs.org/@jridgewell/trace-mapping/-/trace-mapping-0.3.17.tgz",
+      "integrity": "sha512-MCNzAp77qzKca9+W/+I0+sEpaUnZoeasnghNeVc41VZCEKaCH73Vq3BZZ/SzWIgrqE4H4ceI+p+b6C0mHf9T4g==",
+      "dev": true,
+      "requires": {
+        "@jridgewell/resolve-uri": "3.1.0",
+        "@jridgewell/sourcemap-codec": "1.4.14"
+      }
+    },
     "@rollup/plugin-babel": {
       "version": "5.3.0",
       "resolved": "https://registry.npmjs.org/@rollup/plugin-babel/-/plugin-babel-5.3.0.tgz",
@@ -11233,13 +11315,10 @@
       "dev": true
     },
     "json5": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/json5/-/json5-2.2.0.tgz",
-      "integrity": "sha512-f+8cldu7X/y7RAJurMEJmdoKXGB/X550w2Nr3tTbezL6RwEE/iMcm+tZnXeoZtKuOq6ft8+CqzEkrIgx1fPoQA==",
-      "dev": true,
-      "requires": {
-        "minimist": "^1.2.5"
-      }
+      "version": "2.2.3",
+      "resolved": "https://registry.npmjs.org/json5/-/json5-2.2.3.tgz",
+      "integrity": "sha512-XmOWe7eyHYH14cLdVPoyg+GOH3rYX++KpzrylJwSW98t3Nk+U8XOl8FWKOgwtzdb8lXGf6zYwDUzeHMWfxasyg==",
+      "dev": true
     },
     "kleur": {
       "version": "3.0.3",
@@ -11358,20 +11437,14 @@
       "dev": true
     },
     "minimatch": {
-      "version": "3.0.4",
-      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
-      "integrity": "sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==",
+      "version": "3.1.2",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.2.tgz",
+      "integrity": "sha512-J7p63hRiAjw1NDEww1W7i37+ByIrOWO5XQQAzZ3VOcL0PNybwpfmV/N05zFAzwQ9USyEcX6t3UO+K5aqBQOIHw==",
       "dev": true,
       "requires": {
         "brace-expansion": "^1.1.7"
       }
     },
-    "minimist": {
-      "version": "1.2.6",
-      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.6.tgz",
-      "integrity": "sha512-Jsjnk4bw3YJqYzbdyBiNsPWHPfO++UGG749Cxs6peCu5Xg4nrena6OVxOYxrQTqww0Jmwt+Ref8rggumkTLz9Q==",
-      "dev": true
-    },
     "ms": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
@@ -12008,22 +12081,15 @@
       }
     },
     "terser": {
-      "version": "5.10.0",
-      "resolved": "https://registry.npmjs.org/terser/-/terser-5.10.0.tgz",
-      "integrity": "sha512-AMmF99DMfEDiRJfxfY5jj5wNH/bYO09cniSqhfoyxc8sFoYIgkJy86G04UoZU5VjlpnplVu0K6Tx6E9b5+DlHA==",
+      "version": "5.16.1",
+      "resolved": "https://registry.npmjs.org/terser/-/terser-5.16.1.tgz",
+      "integrity": "sha512-xvQfyfA1ayT0qdK47zskQgRZeWLoOQ8JQ6mIgRGVNwZKdQMU+5FkCBjmv4QjcrTzyZquRw2FVtlJSRUmMKQslw==",
       "dev": true,
       "requires": {
+        "@jridgewell/source-map": "^0.3.2",
+        "acorn": "^8.5.0",
         "commander": "^2.20.0",
-        "source-map": "~0.7.2",
         "source-map-support": "~0.5.20"
-      },
-      "dependencies": {
-        "source-map": {
-          "version": "0.7.3",
-          "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.7.3.tgz",
-          "integrity": "sha512-CkCj6giN3S+n9qrYiBTX5gystlENnRW5jZeNLHpe6aue+SrHcG5VYwujhW9s4dY31mEGsxBDrHR6oI69fTXsaQ==",
-          "dev": true
-        }
       }
     },
     "test-exclude": {

From 25e8c2794ca4e56150ef4a86094672245267e02b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Thu, 12 Jan 2023 12:36:53 +0100
Subject: [PATCH 11/15] Small fix encoding url params

---
 src/url.js | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/url.js b/src/url.js
index 000786e..741c337 100644
--- a/src/url.js
+++ b/src/url.js
@@ -47,11 +47,9 @@ export default class Url {
 
     if (source.isSecure()) {
       params.signature = Signature.generate(source, path, new URLSearchParams(params).toString())
-
-      return new URLSearchParams(params)
-    } else {
-      return new URLSearchParams(params)
     }
+
+    return new URLSearchParams(params)
   }
 
   static #encodeEmptyParams (source, path) {

From dc4c7436ac8ae090bc91d4696906aa2e00a1637b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Thu, 12 Jan 2023 18:13:26 +0100
Subject: [PATCH 12/15] Add srcset section to README.md

---
 README.md | 304 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 302 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index c8822e4..3557bc8 100644
--- a/README.md
+++ b/README.md
@@ -142,7 +142,7 @@ Imglab.url('assets', 'image.jpeg', { width: 500, height: 600, mode: 'contain', b
 You can additionally use `Imglab.color` helper function to specify these color values:
 
 ```javascript
-// If you prefer to avoid Imglab scope you can load color helper function in a constant
+// If you prefer to avoid Imglab scope you can load color helper function into a constant
 const color = Imglab.color
 
 // Using color helper for a RGB color
@@ -181,7 +181,7 @@ Imglab.url('assets', 'image.jpeg', { width: 500, height: 500, mode: 'crop', crop
 You can additionally use `Imglab.position` helper function to specify these position values:
 
 ```javascript
-// If you prefer to avoid Imglab scope you can load position helper function in a constant
+// If you prefer to avoid Imglab scope you can load position helper function into a constant
 const position = Imglab.position
 
 // Using position helper for a horizontal and vertical position
@@ -331,6 +331,306 @@ Imglab.url(source, 'logo.png', { width: 300, height: 300, format: 'png' })
 'http://my-company.com:8080/images/logo.png?width=300&height=300&format=png'
 ```
 
+## Generating srcsets
+
+You can use `Imglab.srcset` function to generate custom string values for `srcset` attributes, to be used for Web responsive images inside a `<img>` tag.
+
+This function works similarly to `Imglab.url`, expecting the same parameters and values, except for some specific query parameters that have a special meaning and can receive `Imglab.Range` or `Array` values.
+
+> To learn more about responsive images and the `srcset` attribute, you can take a look to the [MDN article about responsive images](https://developer.mozilla.org/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images).
+
+### Fixed size
+
+When enough information is provided about the image output size (using `width` or `height` parameters), `Imglab.srcset` function will generate a collection of URLs with a default sequence of device pixel ratios.
+
+For the following example we are specying a fixed value of `500` pixels for `width` parameter:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: 500 })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3 3x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=4 4x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=5 5x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=6 6x
+```
+
+A very common practice consists in reducing the quality of images with high pixel density, decreasing the final file size. To achieve this you can optionally specify a `Imglab.Range` object for `quality` parameter, gradually reducing the quality and file size while increasing the image size.
+
+In this example we are specifying a fixed `width` value of `500` pixels and a `quality` range between `80` and `40`:
+
+```javascript
+// If you prefer to avoid Imglab scope you can load range helper function into a constant
+const range = Imglab.range
+
+Imglab.srcset('assets', 'image.jpeg', { width: 500, quality: range(80, 40) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=500&quality=80&dpr=1 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&quality=70&dpr=2 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&quality=61&dpr=3 3x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&quality=53&dpr=4 4x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&quality=46&dpr=5 5x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&quality=40&dpr=6 6x
+```
+
+A custom `range` value can be set for `dpr` parameter too, overriding the default sequence of generated dprs:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: range(1, 4) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3 3x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=4 4x
+```
+
+Using `range` values for `dpr` and `quality` parameters in the same `srcset` call is also possible:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: range(1, 4), quality: range(80, 40) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1&quality=80 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2&quality=63 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3&quality=50 3x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=4&quality=40 4x
+```
+
+If necessary you can also use Arrays with explicit values for `dpr` and `quality`:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: [1, 2, 3], quality: [80, 75, 60] })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1&quality=80 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2&quality=75 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3&quality=60 3x
+```
+
+Or even use a specific `quality` value for all the URLs in the same srcset:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: [1, 2, 3], quality: 70 })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1&quality=70 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2&quality=70 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3&quality=70 3x
+```
+
+### Fluid width
+
+When a specific sequence of width values are required you can use `Imglab.range`, `Imglab.sequence`, or `Array` values for `width` parameter.
+
+When a `range` value is used, a `Imglab.sequence` with a default size of 16 URLs will be generated inside the specified interval:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: range(100, 2000) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=122 122w,
+https://assets.imglab-cdn.net/image.jpeg?width=149 149w,
+https://assets.imglab-cdn.net/image.jpeg?width=182 182w,
+https://assets.imglab-cdn.net/image.jpeg?width=222 222w,
+https://assets.imglab-cdn.net/image.jpeg?width=271 271w,
+https://assets.imglab-cdn.net/image.jpeg?width=331 331w,
+https://assets.imglab-cdn.net/image.jpeg?width=405 405w,
+https://assets.imglab-cdn.net/image.jpeg?width=494 494w,
+https://assets.imglab-cdn.net/image.jpeg?width=603 603w,
+https://assets.imglab-cdn.net/image.jpeg?width=737 737w,
+https://assets.imglab-cdn.net/image.jpeg?width=900 900w,
+https://assets.imglab-cdn.net/image.jpeg?width=1099 1099w,
+https://assets.imglab-cdn.net/image.jpeg?width=1341 1341w,
+https://assets.imglab-cdn.net/image.jpeg?width=1638 1638w,
+https://assets.imglab-cdn.net/image.jpeg?width=2000 2000w
+```
+
+If required you can specify a `range` value for `quality` parameter too:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: range(100, 2000), quality: range(80, 40) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100&quality=80 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=122&quality=76 122w,
+https://assets.imglab-cdn.net/image.jpeg?width=149&quality=73 149w,
+https://assets.imglab-cdn.net/image.jpeg?width=182&quality=70 182w,
+https://assets.imglab-cdn.net/image.jpeg?width=222&quality=66 222w,
+https://assets.imglab-cdn.net/image.jpeg?width=271&quality=63 271w,
+https://assets.imglab-cdn.net/image.jpeg?width=331&quality=61 331w,
+https://assets.imglab-cdn.net/image.jpeg?width=405&quality=58 405w,
+https://assets.imglab-cdn.net/image.jpeg?width=494&quality=55 494w,
+https://assets.imglab-cdn.net/image.jpeg?width=603&quality=53 603w,
+https://assets.imglab-cdn.net/image.jpeg?width=737&quality=50 737w,
+https://assets.imglab-cdn.net/image.jpeg?width=900&quality=48 900w,
+https://assets.imglab-cdn.net/image.jpeg?width=1099&quality=46 1099w,
+https://assets.imglab-cdn.net/image.jpeg?width=1341&quality=44 1341w,
+https://assets.imglab-cdn.net/image.jpeg?width=1638&quality=42 1638w,
+https://assets.imglab-cdn.net/image.jpeg?width=2000&quality=40 2000w
+```
+
+If you want to generate a sequence of numbers for `width` parameter with a specific number of URLs you can use `Imglab.sequence` function helper:
+
+```javascript
+// If you prefer to avoid Imglab scope you can load sequence helper function into a constant
+const sequence = Imglab.sequence
+
+// Generating a srcset string with a sequence of 5 URLs between 100 and 2000 pixels for width parameter
+Imglab.srcset('assets', 'image.jpeg', { width: sequence(100, 2000, 5) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=211 211w,
+https://assets.imglab-cdn.net/image.jpeg?width=447 447w,
+https://assets.imglab-cdn.net/image.jpeg?width=946 946w,
+https://assets.imglab-cdn.net/image.jpeg?width=2000 2000w
+```
+
+Using an Array with specific values will generate URLs only for those widths:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: [100, 300, 500] })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=300 300w,
+https://assets.imglab-cdn.net/image.jpeg?width=500 500w
+```
+
+It is also possible to specify an Array of values for `height` and `quality` parameters:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: [100, 300, 500], height: [200, 400, 600], quality: [75, 70, 65] })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100&height=200&quality=75 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=300&height=400&quality=70 300w,
+https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&quality=65 500w
+```
+
+### No size
+
+When `srcset` function doesn't have information about the image output size (`width` or `height` parameters are not set) it will generate a default `Imglab.sequence` of 16 URLs specifying a `width` value with an interval between `100` and `8192` pixels:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg')
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=134 134w,
+https://assets.imglab-cdn.net/image.jpeg?width=180 180w,
+https://assets.imglab-cdn.net/image.jpeg?width=241 241w,
+https://assets.imglab-cdn.net/image.jpeg?width=324 324w,
+https://assets.imglab-cdn.net/image.jpeg?width=434 434w,
+https://assets.imglab-cdn.net/image.jpeg?width=583 583w,
+https://assets.imglab-cdn.net/image.jpeg?width=781 781w,
+https://assets.imglab-cdn.net/image.jpeg?width=1048 1048w,
+https://assets.imglab-cdn.net/image.jpeg?width=1406 1406w,
+https://assets.imglab-cdn.net/image.jpeg?width=1886 1886w,
+https://assets.imglab-cdn.net/image.jpeg?width=2530 2530w,
+https://assets.imglab-cdn.net/image.jpeg?width=3394 3394w,
+https://assets.imglab-cdn.net/image.jpeg?width=4553 4553w,
+https://assets.imglab-cdn.net/image.jpeg?width=6107 6107w,
+https://assets.imglab-cdn.net/image.jpeg?width=8192 8192w
+```
+
+It is always possible to change this default behavior using `Imglab.sequence` function helper. In the following example we are specifying a sequence of 10 different URLs between `320` and `4096` pixels:
+
+```javascript
+const sequence = Imglab.sequence
+
+Imglab.srcset('assets', 'image.jpeg', { width: sequence(320, 4096, 10) })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=320 320w,
+https://assets.imglab-cdn.net/image.jpeg?width=425 425w,
+https://assets.imglab-cdn.net/image.jpeg?width=564 564w,
+https://assets.imglab-cdn.net/image.jpeg?width=749 749w,
+https://assets.imglab-cdn.net/image.jpeg?width=994 994w,
+https://assets.imglab-cdn.net/image.jpeg?width=1319 1319w,
+https://assets.imglab-cdn.net/image.jpeg?width=1751 1751w,
+https://assets.imglab-cdn.net/image.jpeg?width=2324 2324w,
+https://assets.imglab-cdn.net/image.jpeg?width=3086 3086w,
+https://assets.imglab-cdn.net/image.jpeg?width=4096 4096w
+```
+
+### Image aspect ratio and srcset
+
+A usual scenario is to generate multiple URLs while maintaining the same aspect ratio for all of them. If a specific image aspect ratio is required while using `srcset` function you can set a value to `aspect-ratio` parameter along with `mode` parameter using  `crop`, `contain`, `face`, or `force` resize modes.
+
+For the following example we are using a specific value of `300` pixels for `width`, and an aspect ratio of `1:1` (square), cropping the image with `crop` resize mode and setting output format to `webp`:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: 300, aspectRatio: '1:1', mode: 'crop', format: 'webp' })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=1 1x,
+https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=2 2x,
+https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=3 3x,
+https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=4 4x,
+https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=5 5x,
+https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=6 6x
+```
+
+You can instead use `height` value. In this example we are specifying a fixed value of `300` pixels for `height` parameter, a `aspect-ratio` of `16:9` (widescreen) with `crop` resize mode, and `webp` output format:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { height: 300, aspectRatio: '16:9', mode: 'crop', format: 'webp' })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=1 1x,
+https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=2 2x,
+https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=3 3x,
+https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=4 4x,
+https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=5 5x,
+https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=6 6x
+```
+
+You can also use fluid values for `width` parameter while maintaining the same aspect ratio for all generated URLs. In this example, we are using a `range` value between `100` and `4096` for `width` parameter, a value of `1:1` for `aspect-ratio`, `crop` resize mode and `webp` output format:
+
+```javascript
+Imglab.srcset('assets', 'image.jpeg', { width: range(100, 4096), aspectRatio: '1:1', mode: 'crop', format: 'webp' })
+```
+
+```
+https://assets.imglab-cdn.net/image.jpeg?width=100&aspect-ratio=1%3A1&mode=crop&format=webp 100w,
+https://assets.imglab-cdn.net/image.jpeg?width=128&aspect-ratio=1%3A1&mode=crop&format=webp 128w,
+https://assets.imglab-cdn.net/image.jpeg?width=164&aspect-ratio=1%3A1&mode=crop&format=webp 164w,
+https://assets.imglab-cdn.net/image.jpeg?width=210&aspect-ratio=1%3A1&mode=crop&format=webp 210w,
+https://assets.imglab-cdn.net/image.jpeg?width=269&aspect-ratio=1%3A1&mode=crop&format=webp 269w,
+https://assets.imglab-cdn.net/image.jpeg?width=345&aspect-ratio=1%3A1&mode=crop&format=webp 345w,
+https://assets.imglab-cdn.net/image.jpeg?width=442&aspect-ratio=1%3A1&mode=crop&format=webp 442w,
+https://assets.imglab-cdn.net/image.jpeg?width=566&aspect-ratio=1%3A1&mode=crop&format=webp 566w,
+https://assets.imglab-cdn.net/image.jpeg?width=724&aspect-ratio=1%3A1&mode=crop&format=webp 724w,
+https://assets.imglab-cdn.net/image.jpeg?width=928&aspect-ratio=1%3A1&mode=crop&format=webp 928w,
+https://assets.imglab-cdn.net/image.jpeg?width=1188&aspect-ratio=1%3A1&mode=crop&format=webp 1188w,
+https://assets.imglab-cdn.net/image.jpeg?width=1522&aspect-ratio=1%3A1&mode=crop&format=webp 1522w,
+https://assets.imglab-cdn.net/image.jpeg?width=1949&aspect-ratio=1%3A1&mode=crop&format=webp 1949w,
+https://assets.imglab-cdn.net/image.jpeg?width=2497&aspect-ratio=1%3A1&mode=crop&format=webp 2497w,
+https://assets.imglab-cdn.net/image.jpeg?width=3198&aspect-ratio=1%3A1&mode=crop&format=webp 3198w,
+https://assets.imglab-cdn.net/image.jpeg?width=4096&aspect-ratio=1%3A1&mode=crop&format=webp 4096w
+```
+
 ## License
 
 imglab source code is released under [MIT License](LICENSE).

From ef2180f36e2bc2618f22cb197dd0458faa47c925 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Thu, 12 Jan 2023 18:14:17 +0100
Subject: [PATCH 13/15] Add Range class to default exports

---
 src/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/index.js b/src/index.js
index af46697..a72801d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -13,4 +13,4 @@ const position = Position.position
 const range = Range.range
 const sequence = Sequence.sequence
 
-export default { url, srcset, Source, color, position, range, sequence }
+export default { url, srcset, Source, color, position, Range, range, sequence }

From 4cb2aee03474a022bc9e89a169aa4ed052036331 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Fri, 13 Jan 2023 16:26:01 +0100
Subject: [PATCH 14/15] Add html format to srcset examples

---
 README.md | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/README.md b/README.md
index 3557bc8..f024d4c 100644
--- a/README.md
+++ b/README.md
@@ -333,7 +333,7 @@ Imglab.url(source, 'logo.png', { width: 300, height: 300, format: 'png' })
 
 ## Generating srcsets
 
-You can use `Imglab.srcset` function to generate custom string values for `srcset` attributes, to be used for Web responsive images inside a `<img>` tag.
+You can use `Imglab.srcset` function to generate custom string values for `srcset` attributes, to be used for Web responsive images inside an `<img>` HTML element or picture `<source>`.
 
 This function works similarly to `Imglab.url`, expecting the same parameters and values, except for some specific query parameters that have a special meaning and can receive `Imglab.Range` or `Array` values.
 
@@ -349,7 +349,9 @@ For the following example we are specying a fixed value of `500` pixels for `wid
 Imglab.srcset('assets', 'image.jpeg', { width: 500 })
 ```
 
-```
+Generating the following output:
+
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3 3x,
@@ -369,7 +371,7 @@ const range = Imglab.range
 Imglab.srcset('assets', 'image.jpeg', { width: 500, quality: range(80, 40) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=500&quality=80&dpr=1 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&quality=70&dpr=2 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&quality=61&dpr=3 3x,
@@ -384,7 +386,7 @@ A custom `range` value can be set for `dpr` parameter too, overriding the defaul
 Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: range(1, 4) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3 3x,
@@ -397,7 +399,7 @@ Using `range` values for `dpr` and `quality` parameters in the same `srcset` cal
 Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: range(1, 4), quality: range(80, 40) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1&quality=80 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2&quality=63 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3&quality=50 3x,
@@ -410,7 +412,7 @@ If necessary you can also use Arrays with explicit values for `dpr` and `quality
 Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: [1, 2, 3], quality: [80, 75, 60] })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1&quality=80 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2&quality=75 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3&quality=60 3x
@@ -422,7 +424,7 @@ Or even use a specific `quality` value for all the URLs in the same srcset:
 Imglab.srcset('assets', 'image.jpeg', { width: 500, dpr: [1, 2, 3], quality: 70 })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=1&quality=70 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=2&quality=70 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=500&dpr=3&quality=70 3x
@@ -438,7 +440,7 @@ When a `range` value is used, a `Imglab.sequence` with a default size of 16 URLs
 Imglab.srcset('assets', 'image.jpeg', { width: range(100, 2000) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=122 122w,
 https://assets.imglab-cdn.net/image.jpeg?width=149 149w,
@@ -463,7 +465,7 @@ If required you can specify a `range` value for `quality` parameter too:
 Imglab.srcset('assets', 'image.jpeg', { width: range(100, 2000), quality: range(80, 40) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100&quality=80 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=122&quality=76 122w,
 https://assets.imglab-cdn.net/image.jpeg?width=149&quality=73 149w,
@@ -492,7 +494,7 @@ const sequence = Imglab.sequence
 Imglab.srcset('assets', 'image.jpeg', { width: sequence(100, 2000, 5) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=211 211w,
 https://assets.imglab-cdn.net/image.jpeg?width=447 447w,
@@ -506,7 +508,7 @@ Using an Array with specific values will generate URLs only for those widths:
 Imglab.srcset('assets', 'image.jpeg', { width: [100, 300, 500] })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=300 300w,
 https://assets.imglab-cdn.net/image.jpeg?width=500 500w
@@ -518,7 +520,7 @@ It is also possible to specify an Array of values for `height` and `quality` par
 Imglab.srcset('assets', 'image.jpeg', { width: [100, 300, 500], height: [200, 400, 600], quality: [75, 70, 65] })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100&height=200&quality=75 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=300&height=400&quality=70 300w,
 https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&quality=65 500w
@@ -532,7 +534,7 @@ When `srcset` function doesn't have information about the image output size (`wi
 Imglab.srcset('assets', 'image.jpeg')
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=134 134w,
 https://assets.imglab-cdn.net/image.jpeg?width=180 180w,
@@ -559,7 +561,7 @@ const sequence = Imglab.sequence
 Imglab.srcset('assets', 'image.jpeg', { width: sequence(320, 4096, 10) })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=320 320w,
 https://assets.imglab-cdn.net/image.jpeg?width=425 425w,
 https://assets.imglab-cdn.net/image.jpeg?width=564 564w,
@@ -582,7 +584,7 @@ For the following example we are using a specific value of `300` pixels for `wid
 Imglab.srcset('assets', 'image.jpeg', { width: 300, aspectRatio: '1:1', mode: 'crop', format: 'webp' })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=1 1x,
 https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=2 2x,
 https://assets.imglab-cdn.net/image.jpeg?width=300&aspect-ratio=1%3A1&mode=crop&format=webp&dpr=3 3x,
@@ -597,7 +599,7 @@ You can instead use `height` value. In this example we are specifying a fixed va
 Imglab.srcset('assets', 'image.jpeg', { height: 300, aspectRatio: '16:9', mode: 'crop', format: 'webp' })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=1 1x,
 https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=2 2x,
 https://assets.imglab-cdn.net/image.jpeg?height=300&aspect-ratio=16%3A9&mode=crop&format=webp&dpr=3 3x,
@@ -612,7 +614,7 @@ You can also use fluid values for `width` parameter while maintaining the same a
 Imglab.srcset('assets', 'image.jpeg', { width: range(100, 4096), aspectRatio: '1:1', mode: 'crop', format: 'webp' })
 ```
 
-```
+```html
 https://assets.imglab-cdn.net/image.jpeg?width=100&aspect-ratio=1%3A1&mode=crop&format=webp 100w,
 https://assets.imglab-cdn.net/image.jpeg?width=128&aspect-ratio=1%3A1&mode=crop&format=webp 128w,
 https://assets.imglab-cdn.net/image.jpeg?width=164&aspect-ratio=1%3A1&mode=crop&format=webp 164w,

From 2323824df5b7cbee1b58e7c4f6802daba48c007b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Francisco=20Calvo?=
 <josefranciscocalvo@gmail.com>
Date: Fri, 13 Jan 2023 16:27:38 +0100
Subject: [PATCH 15/15] Upgrade browser header examples to version 0.3.0

---
 README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index f024d4c..e395ed8 100644
--- a/README.md
+++ b/README.md
@@ -34,9 +34,9 @@ If you prefer to use a `script` tag in your code to load `@imglab/core` try to u
 
 ```html
 <!-- Using UNPKG -->
-<script src="https://unpkg.com/@imglab/core@0.2.0/dist/imglab.umd.js"></script>
+<script src="https://unpkg.com/@imglab/core@0.3.0/dist/imglab.umd.js"></script>
 <!-- Or using JDELIVR -->
-<script src="https://cdn.jsdelivr.net/npm/@imglab/core@0.2.0/dist/imglab.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/@imglab/core@0.3.0/dist/imglab.umd.js"></script>
 ```
 
 After adding the library you can use it normally: