5 files changed, 149 insertions, 0 deletions
diff --git a/date-fns/src/getDaysInYear/benchmark.js b/date-fns/src/getDaysInYear/benchmark.js
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index 0000000..b076dc8
--- /dev/null
+++ b/date-fns/src/getDaysInYear/benchmark.js
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+// @flow
+/* eslint-env mocha */
+/* global suite, benchmark */
+
+import getDaysInYear from '.'
+
+suite('getDaysInYear', function () {
+  benchmark('date-fns', function () {
+    return getDaysInYear(this.date)
+  })
+}, {
+  setup: function () {
+    this.date = new Date()
+  }
+})
diff --git a/date-fns/src/getDaysInYear/index.d.ts b/date-fns/src/getDaysInYear/index.d.ts
new file mode 100644
index 0000000..053d44b
--- /dev/null
+++ b/date-fns/src/getDaysInYear/index.d.ts
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+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+import { getDaysInYear } from 'date-fns'
+export default getDaysInYear
diff --git a/date-fns/src/getDaysInYear/index.js.flow b/date-fns/src/getDaysInYear/index.js.flow
new file mode 100644
index 0000000..07bb012
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+++ b/date-fns/src/getDaysInYear/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) => number
diff --git a/date-fns/src/getDaysInYear/index.ts b/date-fns/src/getDaysInYear/index.ts
new file mode 100644
index 0000000..c374a8f
--- /dev/null
+++ b/date-fns/src/getDaysInYear/index.ts
@@ -0,0 +1,36 @@
+import toDate from '../toDate/index'
+import isLeapYear from '../isLeapYear/index'
+import requiredArgs from '../_lib/requiredArgs/index'
+
+/**
+ * @name getDaysInYear
+ * @category Year Helpers
+ * @summary Get the number of days in a year of the given date.
+ *
+ * @description
+ * Get the number of days in a year of the given 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 given date
+ * @returns {Number} the number of days in a year
+ * @throws {TypeError} 1 argument required
+ *
+ * @example
+ * // How many days are in 2012?
+ * const result = getDaysInYear(new Date(2012, 0, 1))
+ * //=> 366
+ */
+export default function getDaysInYear(dirtyDate: Date | number): number {
+  requiredArgs(1, arguments)
+
+  const date = toDate(dirtyDate)
+
+  if (String(new Date(date)) === 'Invalid Date') {
+    return NaN
+  }
+
+  return isLeapYear(date) ? 366 : 365
+}
diff --git a/date-fns/src/getDaysInYear/test.ts b/date-fns/src/getDaysInYear/test.ts
new file mode 100644
index 0000000..8cf2918
--- /dev/null
+++ b/date-fns/src/getDaysInYear/test.ts
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+// @flow
+/* eslint-env mocha */
+
+import assert from 'power-assert'
+import getDaysInYear from '.'
+
+describe('getDaysInYear', function() {
+  it('returns the number of days in the year of the given date', function() {
+    const result = getDaysInYear(new Date(2014, 6 /* Jul */, 2))
+    assert(result === 365)
+  })
+
+  it('works for a leap year', function() {
+    const result = getDaysInYear(new Date(2012, 6 /* Jul */, 2))
+    assert(result === 366)
+  })
+
+  it('works for the years divisible by 100 but not by 400', function() {
+    const result = getDaysInYear(new Date(2100, 6 /* Jul */, 2))
+    assert(result === 365)
+  })
+
+  it('works for the years divisible by 400', function() {
+    const result = getDaysInYear(new Date(2000, 6 /* Jul */, 2))
+    assert(result === 366)
+  })
+
+  it('accepts a timestamp', function() {
+    const date = new Date(2012, 6 /* Jul */, 2).getTime()
+    const result = getDaysInYear(date)
+    assert(result === 366)
+  })
+
+  it('returns NaN if the given date is invalid', function() {
+    const result = getDaysInYear(new Date(NaN))
+    assert(isNaN(result))
+  })
+
+  it('throws TypeError exception if passed less than 1 argument', function() {
+    assert.throws(getDaysInYear.bind(null), TypeError)
+  })
+})