5 files changed, 144 insertions, 0 deletions
diff --git a/date-fns/src/startOfISOWeek/benchmark.js b/date-fns/src/startOfISOWeek/benchmark.js
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index 0000000..2ddb09b
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+++ b/date-fns/src/startOfISOWeek/benchmark.js
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+// @flow
+/* eslint-env mocha */
+/* global suite, benchmark */
+
+import startOfISOWeek from '.'
+import moment from 'moment'
+
+suite('startOfISOWeek', function () {
+  benchmark('date-fns', function () {
+    return startOfISOWeek(this.date)
+  })
+
+  benchmark('Moment.js', function () {
+    return this.moment.startOf('isoWeek')
+  })
+}, {
+  setup: function () {
+    this.date = new Date()
+    this.moment = moment()
+  }
+})
diff --git a/date-fns/src/startOfISOWeek/index.d.ts b/date-fns/src/startOfISOWeek/index.d.ts
new file mode 100644
index 0000000..93e573a
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+++ b/date-fns/src/startOfISOWeek/index.d.ts
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+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+import { startOfISOWeek } from 'date-fns'
+export default startOfISOWeek
diff --git a/date-fns/src/startOfISOWeek/index.js.flow b/date-fns/src/startOfISOWeek/index.js.flow
new file mode 100644
index 0000000..4b7c616
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+++ b/date-fns/src/startOfISOWeek/index.js.flow
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+// @flow
+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+export type Interval = {
+  start: Date | number,
+  end: Date | number,
+}
+
+export type Locale = {
+  code?: string,
+  formatDistance?: (...args: Array<any>) => any,
+  formatRelative?: (...args: Array<any>) => any,
+  localize?: {
+    ordinalNumber: (...args: Array<any>) => any,
+    era: (...args: Array<any>) => any,
+    quarter: (...args: Array<any>) => any,
+    month: (...args: Array<any>) => any,
+    day: (...args: Array<any>) => any,
+    dayPeriod: (...args: Array<any>) => any,
+  },
+  formatLong?: {
+    date: (...args: Array<any>) => any,
+    time: (...args: Array<any>) => any,
+    dateTime: (...args: Array<any>) => any,
+  },
+  match?: {
+    ordinalNumber: (...args: Array<any>) => any,
+    era: (...args: Array<any>) => any,
+    quarter: (...args: Array<any>) => any,
+    month: (...args: Array<any>) => any,
+    day: (...args: Array<any>) => any,
+    dayPeriod: (...args: Array<any>) => any,
+  },
+  options?: {
+    weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6,
+    firstWeekContainsDate?: 1 | 2 | 3 | 4 | 5 | 6 | 7,
+  },
+}
+
+export type Duration = {
+  years?: number,
+  months?: number,
+  weeks?: number,
+  days?: number,
+  hours?: number,
+  minutes?: number,
+  seconds?: number,
+}
+
+export type Day = 0 | 1 | 2 | 3 | 4 | 5 | 6
+
+declare module.exports: (date: Date | number) => Date
diff --git a/date-fns/src/startOfISOWeek/index.ts b/date-fns/src/startOfISOWeek/index.ts
new file mode 100644
index 0000000..e4d8718
--- /dev/null
+++ b/date-fns/src/startOfISOWeek/index.ts
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+import startOfWeek from '../startOfWeek/index'
+import requiredArgs from '../_lib/requiredArgs/index'
+
+/**
+ * @name startOfISOWeek
+ * @category ISO Week Helpers
+ * @summary Return the start of an ISO week for the given date.
+ *
+ * @description
+ * Return the start of an ISO week for the given date.
+ * The result will be in the local timezone.
+ *
+ * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
+ *
+ * ### v2.0.0 breaking changes:
+ *
+ * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
+ *
+ * @param {Date|Number} date - the original date
+ * @returns {Date} the start of an ISO week
+ * @throws {TypeError} 1 argument required
+ *
+ * @example
+ * // The start of an ISO week for 2 September 2014 11:55:00:
+ * var result = startOfISOWeek(new Date(2014, 8, 2, 11, 55, 0))
+ * //=> Mon Sep 01 2014 00:00:00
+ */
+export default function startOfISOWeek(dirtyDate: Date | number): Date {
+  requiredArgs(1, arguments)
+
+  return startOfWeek(dirtyDate, { weekStartsOn: 1 })
+}
diff --git a/date-fns/src/startOfISOWeek/test.ts b/date-fns/src/startOfISOWeek/test.ts
new file mode 100644
index 0000000..6e96187
--- /dev/null
+++ b/date-fns/src/startOfISOWeek/test.ts
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+// @flow
+/* eslint-env mocha */
+
+import assert from 'power-assert'
+import startOfISOWeek from '.'
+
+describe('startOfISOWeek', function() {
+  it('returns the date with the time set to 00:00:00 and the date set to the first day of an ISO week', function() {
+    const date = new Date(2014, 8 /* Sep */, 2, 11, 55, 0)
+    const result = startOfISOWeek(date)
+    assert.deepEqual(result, new Date(2014, 8 /* Sep */, 1))
+  })
+
+  it('accepts a timestamp', function() {
+    const date = new Date(2014, 1 /* Feb */, 11, 11, 55, 0).getTime()
+    const result = startOfISOWeek(date)
+    assert.deepEqual(result, new Date(2014, 1 /* Feb */, 10))
+  })
+
+  it('does not mutate the original date', function() {
+    const date = new Date(2014, 8 /* Sep */, 2, 11, 55, 0)
+    startOfISOWeek(date)
+    assert.deepEqual(date, new Date(2014, 8 /* Sep */, 2, 11, 55, 0))
+  })
+
+  it('returns `Invalid Date` if the given date is invalid', function() {
+    const result = startOfISOWeek(new Date(NaN))
+    //@ts-expect-error
+    assert(result instanceof Date && isNaN(result))
+  })
+
+  it('throws TypeError exception if passed less than 1 argument', function() {
+    assert.throws(startOfISOWeek.bind(null), TypeError)
+  })
+})