chore: create library for year query format (#89)

## Description

- Year schema library verifies that the value of year is an integer of
length 4 and returns error statements if not
- In certain use cases it is optional so it remains optional in only
those situations, along with situations where it must be converted to a
number.

## Related Issue

Closes #73 

## Motivation and Context

- Simplifies code making it easier to read.

## How Has This Been Tested?

- Ran locally with comparisons using postman.


## Types of changes

<!--- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)

## Checklist:

<!--- Go over all the following points, and put an `x` in all the boxes
that apply. -->
<!--- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->

- [ ] My code involves a change to the database schema.
- [ ] My code requires a change to the documentation.

apps/api/src/schema/calendar.ts

@@ -1,14 +1,9 @@
 import { z } from "@hono/zod-openapi";
 import { terms } from "@packages/db/schema";
+import { yearSchema } from "./lib";
 
 export const calendarQuerySchema = z.object({
-  year: z
-    .string({ message: "Parameter 'year' is required" })
-    .length(4, { message: "Parameter 'year' must have length 4" })
-    .refine((x) => !Number.isNaN(Number.parseInt(x, 10)), {
-      message: "Parameter 'year' must be an integer",
-    })
-    .openapi({ param: { name: "year", in: "query" }, example: "2024" }),
+  year: yearSchema.openapi({ param: { name: "year", in: "query" } }),
   quarter: z
     .enum(terms, {
       message:

apps/api/src/schema/enrollment-history.ts

@@ -1,12 +1,10 @@
 import { z } from "@hono/zod-openapi";
 import { terms, websocSectionTypes, websocStatuses } from "@packages/db/schema";
+import { yearSchema } from "./lib";
 
 export const enrollmentHistoryQuerySchema = z
   .object({
-    year: z
-      .string()
-      .regex(/^\d{4}$/, { message: "Invalid year provided" })
-      .optional(),
+    year: yearSchema.optional(),
     quarter: z.enum(terms, { invalid_type_error: "Invalid quarter provided" }).optional(),
     instructorName: z.string().optional(),
     department: z.string().optional(),

apps/api/src/schema/grades.ts

@@ -1,5 +1,6 @@
 import { z } from "@hono/zod-openapi";
 import { courseLevels, terms } from "@packages/db/schema";
+import { yearSchema } from "./lib";
 
 const geCategories = [
   "GE-1A",
@@ -15,10 +16,7 @@ const geCategories = [
 ] as const;
 
 export const gradesQuerySchema = z.object({
-  year: z
-    .string()
-    .regex(/^\d{4}$/, { message: "Invalid year provided" })
-    .optional(),
+  year: yearSchema.optional(),
   quarter: z.enum(terms, { invalid_type_error: "Invalid quarter provided" }).optional(),
   instructor: z.string().optional(),
   department: z.string().optional(),

apps/api/src/schema/larc.ts

@@ -1,6 +1,6 @@
 import { z } from "@hono/zod-openapi";
 import { terms } from "@packages/db/schema";
-import { courseNumberSchema, daysSchema, timeSchema } from "./lib";
+import { courseNumberSchema, daysSchema, timeSchema, yearSchema } from "./lib";
 
 export const larcQuerySchema = z.object({
   instructorName: z
@@ -18,10 +18,7 @@ export const larcQuerySchema = z.object({
   courseNumber: courseNumberSchema
     .optional()
     .openapi({ description: "The course number(s) of the LARC section's related course." }),
-  year: z
-    .string({ message: "Parameter 'year' is required " })
-    .regex(/^\d{4}$/, { message: "Invalid year provided" })
-    .openapi({ description: "The year of the LARC section", example: "2024" }),
+  year: yearSchema,
   quarter: z
     .enum(terms, {
       message:

apps/api/src/schema/lib/index.ts

@@ -1,3 +1,4 @@
 export * from "./time.ts";
 export * from "./day.ts";
 export * from "./course.ts";
+export * from "./year.ts";

apps/api/src/schema/lib/year.ts

@@ -0,0 +1,15 @@
+import { z } from "@hono/zod-openapi";
+
+/**
+ * Expects a string forming a four-digit positive integer
+ */
+
+export const yearSchema = z.coerce
+  .string()
+  .refine((val) => val !== ("" || "undefined" || "null"), {
+    message: "Parameter 'year' is required",
+  })
+  .refine((val) => /^\d{4}$/.test(val), {
+    message: "Year must be a 4-digit positive integer",
+  })
+  .openapi({ example: "2024" });

apps/api/src/schema/websoc.ts

@@ -2,7 +2,7 @@ import { z } from "@hono/zod-openapi";
 import type { FinalExamStatus } from "@packages/db/schema";
 import { courseLevels, terms, websocSectionTypes, websocStatuses } from "@packages/db/schema";
 import { isBaseTenInt } from "@packages/stdlib";
-import { courseNumberSchema, daysSchema, timeSchema } from "./lib";
+import { courseNumberSchema, daysSchema, timeSchema, yearSchema } from "./lib";
 
 const anyArray = ["ANY"] as const;
 
@@ -73,9 +73,7 @@ const isValidRestrictionCode = (code: string): code is (typeof restrictionCodes)
   (restrictionCodes as readonly string[]).includes(code);
 
 export const websocQuerySchema = z.object({
-  year: z
-    .string({ message: "Parameter 'year' is required " })
-    .length(4, { message: "Parameter 'year' must have length 4" }),
+  year: yearSchema,
   quarter: z.enum(terms, { required_error: "Parameter 'quarter' is required" }),
   ge: z
     .enum(geCategories)

apps/api/src/schema/week.ts

@@ -1,15 +1,12 @@
 import { z } from "@hono/zod-openapi";
+import { yearSchema } from "./lib";
 const shortMonths = [4, 6, 9, 11];
 
 const isLeap = (x: number) => x % 4 === 0 && (x % 100 === 0 ? x % 400 === 0 : true);
 
 export const weekQuerySchema = z
   .object({
-    year: z.coerce
-      .number()
-      .refine((x) => x.toString().length === 4, { message: "Parameter 'year' must have length 4" })
-      .openapi({ example: 2024 })
-      .optional(),
+    year: yearSchema.transform((x) => Number.parseInt(x, 10)).optional(),
     month: z.coerce
       .number()
       .refine((x) => 1 <= x && x <= 12, {