chore: some more contributor docs and remove passing jscodeshift to t…

…ransform hook

README.md

@@ -14,7 +14,9 @@ And it will automatically clean up any unneeded dependencies.
 
 ## Contributing
 
-If you would like to contribute a codemod for a module in [module replacements](https://github.com/es-tooling/module-replacements), please feel free to create a pull request! If you're interested in contributing a codemod, but don't have much experience with _writing_ codemods, take a look at [codemod.studio](https://codemod.com/studio), which makes it really easy.
+If you would like to contribute a codemod for a module in [module replacements](https://github.com/es-tooling/module-replacements), please feel free to create a pull request! Pick any module from [module replacements](https://github.com/es-tooling/module-replacements), collect some before/after examples, and get started.
+
+> If you're interested in contributing a codemod, but don't have much experience with _writing_ codemods, take a look at [codemod.studio](https://codemod.com/studio), which makes it really easy.
 
 To start, you can fork and clone this project. Then execute the following steps:
 
@@ -34,3 +36,22 @@ This will scaffold all the needed files to create the codemod, and scaffold some
 - `test/fixtures/is-array-buffer/case-1/after.js`: The expected _after_ state of the code after applying your codemod
 
 You can take a look at an existing codemod under the `./codemods/*` folder as a reference implementation; most of them are very small.
+
+### Codemod implementation
+
+A codemod is a function that gets passed an options object, and returns an object. Here's an example:
+
+```js
+export default function (options) {
+  return {
+    name: "foo-lib",
+    transform: ({ file }) => {
+      return file.source.replaceAll("foo", "bar");
+    },
+  };
+}
+```
+
+The codemod's `name` should be equal to the name of the package that you're trying to replace (which should be a package from [module replacements](https://github.com/es-tooling/module-replacements)). So if you're writing a codemod for `is-array-buffer`, the `name` of the codemod should be `is-array-buffer`.
+
+The `transform` function is where you can implement your codemod magic. Feel free to use whatever codemod tool you're comfortable with, [ast-grep](https://github.com/ast-grep/ast-grep), [jscodeshift](https://github.com/facebook/jscodeshift), etc. It gets passed the `file` with a `source` property which is a string containing the contents of the file, which you can use to perform transformations on. Make sure to return the changed file from the `transform` function.

biome.json

@@ -1,8 +1,8 @@
 {
-	"$schema": "https://biomejs.dev/schemas/1.8.3/schema.json",
-	"organizeImports": {
-		"enabled": true
-	},
+  "$schema": "https://biomejs.dev/schemas/1.8.3/schema.json",
+  "organizeImports": {
+    "enabled": true
+  },
   "files": {
     "ignore": ["node_modules/*", "test/fixtures/*"]
   },

codemods/is-array-buffer/index.js

@@ -1,3 +1,5 @@
+import jscodeshift from 'jscodeshift';
+
 /**
  * @typedef {import('../../types.js').Codemod} Codemod
  * @typedef {import('../../types.js').CodemodOptions} CodemodOptions
@@ -10,7 +12,7 @@
 export default function (options) {
 	return {
 		name: 'is-array-buffer',
-		transform: ({ file, jscodeshift }) => {
+		transform: ({ file }) => {
 			const j = jscodeshift;
 			const root = j(file.source);
 			let dirtyFlag = false;

codemods/is-boolean-object/index.js

@@ -1,3 +1,5 @@
+import jscodeshift from 'jscodeshift';
+
 /**
  * @typedef {import('../../types.js').Codemod} Codemod
  * @typedef {import('../../types.js').CodemodOptions} CodemodOptions
@@ -10,7 +12,7 @@
 export default function (options) {
 	return {
 		name: 'is-boolean-object',
-		transform: ({ file, jscodeshift }) => {
+		transform: ({ file }) => {
 			const j = jscodeshift;
 			const root = j(file.source);
 			let dirtyFlag = false;

codemods/is-whitespace/index.js

@@ -1,3 +1,5 @@
+import jscodeshift from 'jscodeshift';
+
 /**
  * @typedef {import('../../types.js').Codemod} Codemod
  * @typedef {import('../../types.js').CodemodOptions} CodemodOptions
@@ -16,7 +18,7 @@
 export default function (options) {
 	return {
 		name: 'is-whitespace',
-		transform: ({ file, jscodeshift }) => {
+		transform: ({ file }) => {
 			const j = jscodeshift;
 			const root = j(file.source);
 

index.js

@@ -1,7 +1,6 @@
 #!/usr/bin/env node
 
 import fg from 'fast-glob';
-import jscodeshift from 'jscodeshift';
 import picocolors from 'picocolors';
 import { readFile } from 'fs/promises';
 import { codemods } from './codemods/index.js';
@@ -26,7 +25,6 @@ await Promise.all(entries.map(async (entry) => {
           source,
           filename: entry
         },
-        jscodeshift
       });
 
       if (source !== result) {

test/codemod.test.js

@@ -1,4 +1,3 @@
-import jscodeshift from 'jscodeshift';
 import { describe, it } from 'node:test';
 import fs from 'node:fs';
 import assert from 'assert';
@@ -34,7 +33,6 @@ describe('codemod', () => {
 							filename,
 							source: before,
 						},
-						jscodeshift,
 					});
 					fs.writeFileSync(
 						`./test/fixtures/${codemod.name}/${fixture}/result.js`,

types.ts

@@ -1,5 +1,3 @@
-import type jscodeshift from "jscodeshift";
-
 export interface CodemodOptions {
 }
 
@@ -14,5 +12,5 @@ export interface Codemod {
    * you're trying to replace
    */
   name: string;
-  transform: (options: { file: File, jscodeshift: typeof jscodeshift }) => string | Promise<string>;
+  transform: (options: { file: File }) => string | Promise<string>;
 }