Migrate startOfWeekYear function

src/startOfWeekYear/index.js → src/startOfWeekYear/index.ts

@@ -2,6 +2,7 @@ import getWeekYear from '../getWeekYear/index'
 import startOfWeek from '../startOfWeek/index'
 import toInteger from '../_lib/toInteger/index'
 import requiredArgs from '../_lib/requiredArgs/index'
+import { LocaleOptions, FirstWeekContainsDateOptions } from '../types'
 
 /**
  * @name startOfWeekYear
@@ -33,39 +34,42 @@ import requiredArgs from '../_lib/requiredArgs/index'
  *
  * @example
  * // The start of an a week-numbering year for 2 July 2005 with default settings:
- * var result = startOfWeekYear(new Date(2005, 6, 2))
+ * const result = startOfWeekYear(new Date(2005, 6, 2))
  * //=> Sun Dec 26 2004 00:00:00
  *
  * @example
  * // The start of a week-numbering year for 2 July 2005
  * // if Monday is the first day of week
  * // and 4 January is always in the first week of the year:
- * var result = startOfWeekYear(new Date(2005, 6, 2), {
+ * const result = startOfWeekYear(new Date(2005, 6, 2), {
  *   weekStartsOn: 1,
  *   firstWeekContainsDate: 4
  * })
  * //=> Mon Jan 03 2005 00:00:00
  */
-export default function startOfWeekYear(dirtyDate, dirtyOptions) {
+export default function startOfWeekYear(
+  dirtyDate: Date | number,
+  dirtyOptions?: LocaleOptions & FirstWeekContainsDateOptions
+): Date {
   requiredArgs(1, arguments)
 
-  var options = dirtyOptions || {}
-  var locale = options.locale
-  var localeFirstWeekContainsDate =
+  const options = dirtyOptions || {}
+  const locale = options.locale
+  const localeFirstWeekContainsDate =
     locale && locale.options && locale.options.firstWeekContainsDate
-  var defaultFirstWeekContainsDate =
+  const defaultFirstWeekContainsDate =
     localeFirstWeekContainsDate == null
       ? 1
       : toInteger(localeFirstWeekContainsDate)
-  var firstWeekContainsDate =
+  const firstWeekContainsDate =
     options.firstWeekContainsDate == null
       ? defaultFirstWeekContainsDate
       : toInteger(options.firstWeekContainsDate)
 
-  var year = getWeekYear(dirtyDate, dirtyOptions)
-  var firstWeek = new Date(0)
+  const year = getWeekYear(dirtyDate, dirtyOptions)
+  const firstWeek = new Date(0)
   firstWeek.setFullYear(year, 0, firstWeekContainsDate)
   firstWeek.setHours(0, 0, 0, 0)
-  var date = startOfWeek(firstWeek, dirtyOptions)
+  const date = startOfWeek(firstWeek, dirtyOptions)
   return date
 }

src/startOfWeekYear/test.ts

@@ -0,0 +1,86 @@
+/* eslint-env mocha */
+
+import assert from 'assert'
+import startOfWeekYear from '.'
+
+describe('startOfWeekYear', function () {
+  it('returns the date with the time set to 00:00:00 and the date set to the first day of a week year', function () {
+    const result = startOfWeekYear(new Date(2005, 6 /* Jul */, 2))
+    assert.deepStrictEqual(result, new Date(2004, 11 /* Dec */, 26, 0, 0, 0, 0))
+  })
+
+  it('accepts a timestamp', function () {
+    const result = startOfWeekYear(
+      new Date(2005, 0 /* Jan */, 1, 6, 0).getTime()
+    )
+    assert.deepStrictEqual(result, new Date(2004, 11 /* Dec */, 26, 0, 0, 0, 0))
+  })
+
+  it('does not mutate the original date', function () {
+    const date = new Date(2014, 6 /* Jul */, 2)
+    startOfWeekYear(date)
+    assert.deepStrictEqual(date, new Date(2014, 6 /* Jul */, 2))
+  })
+
+  it('handles dates before 100 AD', function () {
+    const initialDate = new Date(0)
+    initialDate.setFullYear(9, 0 /* Jan */, 1)
+    initialDate.setHours(0, 0, 0, 0)
+    const expectedResult = new Date(0)
+    expectedResult.setFullYear(8, 11 /* Dec */, 28)
+    expectedResult.setHours(0, 0, 0, 0)
+    const result = startOfWeekYear(initialDate)
+    assert.deepStrictEqual(result, expectedResult)
+  })
+
+  it('returns `Invalid Date` if the given date is invalid', function () {
+    const result = startOfWeekYear(new Date(NaN))
+    //@ts-expect-error
+    assert(result instanceof Date && isNaN(result))
+  })
+
+  it('allows to specify `weekStartsOn` and `firstWeekContainsDate` in locale', function () {
+    const date = new Date(2005, 6 /* Jul */, 2)
+    const result = startOfWeekYear(date, {
+      // @ts-expect-error
+      locale: {
+        options: { weekStartsOn: 1, firstWeekContainsDate: 4 },
+      },
+    })
+    assert.deepStrictEqual(result, new Date(2005, 0 /* Jan */, 3, 0, 0, 0, 0))
+  })
+
+  it('`options.weekStartsOn` overwrites the first day of the week specified in locale', function () {
+    const date = new Date(2005, 6 /* Jul */, 2)
+    const result = startOfWeekYear(date, {
+      weekStartsOn: 1,
+      firstWeekContainsDate: 4,
+      // @ts-expect-error
+      locale: {
+        options: { weekStartsOn: 0, firstWeekContainsDate: 1 },
+      },
+    })
+    assert.deepStrictEqual(result, new Date(2005, 0 /* Jan */, 3, 0, 0, 0, 0))
+  })
+
+  it('throws `RangeError` if `options.weekStartsOn` is not convertable to 0, 1, ..., 6 or undefined', function () {
+    // @ts-expect-error
+    const block = startOfWeekYear.bind(null, new Date(2007, 11 /* Dec */, 31), {
+      weekStartsOn: NaN,
+    })
+    assert.throws(block, RangeError)
+  })
+
+  it('throws `RangeError` if `options.firstWeekContainsDate` is not convertable to 1, 2, ..., 7 or undefined', function () {
+    // @ts-expect-error
+    const block = startOfWeekYear.bind(null, new Date(2007, 11 /* Dec */, 31), {
+      firstWeekContainsDate: NaN,
+    })
+    assert.throws(block, RangeError)
+  })
+
+  it('throws TypeError exception if passed less than 1 argument', function () {
+    //@ts-expect-error
+    assert.throws(startOfWeekYear.bind(null), TypeError)
+  })
+})

src/types.ts

@@ -55,9 +55,4 @@ export interface DateValues {
   milliseconds?: number
 }
 
-export type Unit = 'second'
-  | 'minute'
-  | 'hour'
-  | 'day'
-  | 'month'
-  | 'year';
+export type Unit = 'second' | 'minute' | 'hour' | 'day' | 'month' | 'year'