chore: draft add isoWeek plugin (#771)

src/plugin/isoWeekOfYear/index.js

@@ -0,0 +1,32 @@
+export default (o, c, d) => {
+  const days = function (day) {
+    const weekDay = day.day()
+    return weekDay === 0 ? 7 : weekDay
+  }
+
+  const getYearFirstThursday = function (year) {
+    const yearFirstDay = d().year(year).startOf('year')
+    let addDiffDays = 4 - days(yearFirstDay)
+    if (days(yearFirstDay) > 4) {
+      addDiffDays += 7
+    }
+    return yearFirstDay.add(addDiffDays, 'day')
+  }
+
+  const proto = c.prototype
+
+  proto.isoWeekYear = function () {
+    const nowWeekThursday = d(this).add((4 - days(this)), 'day')
+    return nowWeekThursday.year()
+  }
+
+  proto.isoWeek = function (isoWeek = null) {
+    if (isoWeek !== null) {
+      return this.add((isoWeek - this.isoWeek()) * 7, 'day')
+    }
+
+    const nowWeekThursday = d(this).add((4 - days(this)), 'day')
+    const diffWeekThursday = getYearFirstThursday(this.isoWeekYear())
+    return nowWeekThursday.diff(diffWeekThursday, 'week') + 1
+  }
+}

test/plugin/isoWeekOfYear.test.js

@@ -0,0 +1,96 @@
+import MockDate from 'mockdate'
+import dayjs from '../../src'
+import isoWeekOfYear from '../../src/plugin/isoWeekOfYear'
+
+dayjs.extend(isoWeekOfYear)
+
+beforeEach(() => {
+  MockDate.set(new Date())
+})
+
+afterEach(() => {
+  MockDate.reset()
+})
+
+it('isoWeek of year', () => {
+  expect(dayjs().isoWeek(1).isoWeek()).toBe(1)
+  expect(dayjs().isoWeek(27).isoWeek()).toBe(27)
+
+
+  expect(dayjs('20191223').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191223').isoWeek()).toBe(52)
+  expect(dayjs('20191224').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191224').isoWeek()).toBe(52)
+  expect(dayjs('20191225').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191225').isoWeek()).toBe(52)
+  expect(dayjs('20191226').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191226').isoWeek()).toBe(52)
+  expect(dayjs('20191227').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191227').isoWeek()).toBe(52)
+  expect(dayjs('20191228').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191228').isoWeek()).toBe(52)
+  expect(dayjs('20191229').isoWeekYear()).toBe(2019)
+  expect(dayjs('20191229').isoWeek()).toBe(52)
+
+  expect(dayjs('20191230').isoWeekYear()).toBe(2020)
+  expect(dayjs('20191230').isoWeek()).toBe(1)
+  expect(dayjs('20191231').isoWeekYear()).toBe(2020)
+  expect(dayjs('20191231').isoWeek()).toBe(1)
+  expect(dayjs('20200101').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200101').isoWeek()).toBe(1)
+  expect(dayjs('20200102').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200102').isoWeek()).toBe(1)
+  expect(dayjs('20200103').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200103').isoWeek()).toBe(1)
+  expect(dayjs('20200104').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200104').isoWeek()).toBe(1)
+  expect(dayjs('20200105').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200105').isoWeek()).toBe(1)
+
+  expect(dayjs('20200106').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200106').isoWeek()).toBe(2)
+  expect(dayjs('20200107').isoWeekYear()).toBe(2020)
+  expect(dayjs('20200107').isoWeek()).toBe(2)
+
+
+  expect(dayjs('20201223').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201223').isoWeek()).toBe(52)
+  expect(dayjs('20201224').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201224').isoWeek()).toBe(52)
+  expect(dayjs('20201225').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201225').isoWeek()).toBe(52)
+  expect(dayjs('20201226').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201226').isoWeek()).toBe(52)
+  expect(dayjs('20201227').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201227').isoWeek()).toBe(52)
+
+  expect(dayjs('20201228').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201228').isoWeek()).toBe(53)
+  expect(dayjs('20201229').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201229').isoWeek()).toBe(53)
+  expect(dayjs('20201230').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201230').isoWeek()).toBe(53)
+  expect(dayjs('20201231').isoWeekYear()).toBe(2020)
+  expect(dayjs('20201231').isoWeek()).toBe(53)
+  expect(dayjs('20210101').isoWeekYear()).toBe(2020)
+  expect(dayjs('20210101').isoWeek()).toBe(53)
+  expect(dayjs('20210102').isoWeekYear()).toBe(2020)
+  expect(dayjs('20210102').isoWeek()).toBe(53)
+  expect(dayjs('20210103').isoWeekYear()).toBe(2020)
+  expect(dayjs('20210103').isoWeek()).toBe(53)
+
+  expect(dayjs('20210104').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210104').isoWeek()).toBe(1)
+  expect(dayjs('20210105').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210105').isoWeek()).toBe(1)
+  expect(dayjs('20210106').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210106').isoWeek()).toBe(1)
+  expect(dayjs('20210107').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210107').isoWeek()).toBe(1)
+  expect(dayjs('20210108').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210108').isoWeek()).toBe(1)
+  expect(dayjs('20210109').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210109').isoWeek()).toBe(1)
+  expect(dayjs('20210110').isoWeekYear()).toBe(2021)
+  expect(dayjs('20210110').isoWeek()).toBe(1)
+})

types/plugin/isoWeekOfYear.d.ts

@@ -0,0 +1,13 @@
+import { PluginFunc } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
+
+declare module 'dayjs' {
+  interface Dayjs {
+    isoWeekYear(): number
+    isoWeek(): number
+
+    isoWeek(value: number): Dayjs
+  }
+}