added new duration plugin

src/constant.js

@@ -1,7 +1,10 @@
+export const MONTHS_A_YEAR = 12
+export const DAYS_A_WEEK = 7
+
 export const SECONDS_A_MINUTE = 60
 export const SECONDS_A_HOUR = SECONDS_A_MINUTE * 60
 export const SECONDS_A_DAY = SECONDS_A_HOUR * 24
-export const SECONDS_A_WEEK = SECONDS_A_DAY * 7
+export const SECONDS_A_WEEK = SECONDS_A_DAY * DAYS_A_WEEK
 
 export const MILLISECONDS_A_SECOND = 1e3
 export const MILLISECONDS_A_MINUTE = SECONDS_A_MINUTE * MILLISECONDS_A_SECOND

src/plugin/duration/index.js

@@ -0,0 +1,76 @@
+import * as C from '../../constant'
+
+const dayStart = dt => dt.startOf(C.D)
+
+function dayDiff(earlier, later) {
+  return Math.floor(dayStart(later).diff(dayStart(earlier)) / C.MILLISECONDS_A_DAY)
+}
+
+function highOrderDiffs(cursor, later, isPast) {
+  const differs = [
+    [C.Y, (a, b) => b.year() - a.year()],
+    [C.M, (a, b) => (b.month() - a.month()) + ((b.year() - a.year()) * C.MONTHS_A_YEAR)],
+    [C.D, dayDiff]
+  ]
+  const results = {}
+  let cdelta
+  for (const [unit, differ] of differs) {
+    let delta = differ(cursor, later)
+    cdelta = cursor.add(delta, unit)
+    if (cdelta > later) {
+      delta -= 1
+      cursor = cursor.add(delta, unit)
+    } else {
+      cursor = cdelta
+    }
+    results[unit] = isPast ? -1 * delta : delta
+  }
+  return [cursor, results]
+}
+
+function lowerOrderDiffs(rms, isPast) {
+  const differs = [
+    [C.H, ms => Math.floor(ms / C.MILLISECONDS_A_HOUR),
+      (ms, h) => ms - (h * C.MILLISECONDS_A_HOUR)
+    ],
+    [C.MIN, ms => Math.floor(ms / C.MILLISECONDS_A_MINUTE),
+      (ms, m) => ms - (m * C.MILLISECONDS_A_MINUTE)
+    ],
+    [C.S, ms => Math.floor(ms / C.MILLISECONDS_A_SECOND),
+      (ms, s) => ms - (s * C.MILLISECONDS_A_SECOND)
+    ],
+    [C.MS, ms => Math.floor(ms)]
+  ]
+  const results = {}
+  let delta = 0
+  for (const [unit, differ, rimender] of differs) {
+    if (rms > 0) {
+      delta = differ(rms)
+      if (delta >= 0 && unit !== C.MS) {
+        rms = rimender(rms, delta)
+      } else {
+        rms = 0
+      }
+    }
+    results[unit] = isPast ? -1 * delta : delta
+    delta = 0
+  }
+  return results
+}
+
+export default (o, c, d) => {
+  const proto = c.prototype
+  proto.duration = function (input) {
+    const instance = d(this)
+    const that = d(input)
+    const isPast = instance > that
+    const earlier = isPast ? that : instance
+    const later = isPast ? instance : that
+
+    const [cursor, results] = highOrderDiffs(earlier, later, isPast)
+
+    const remainingMillis = later - cursor
+
+    return Object.assign(results, lowerOrderDiffs(remainingMillis, isPast))
+  }
+}

test/plugin/duration.test.js

@@ -0,0 +1,81 @@
+import MockDate from 'mockdate'
+import dayjs from '../../src'
+import duration from '../../src/plugin/duration'
+
+dayjs.extend(duration)
+
+beforeEach(() => {
+  MockDate.set(new Date())
+})
+
+afterEach(() => {
+  MockDate.reset()
+})
+
+it('duration between dates', () => {
+  const dayjsA = dayjs('2019-03-31')
+  const dayjsB = dayjs('2019-04-1')
+  const dayjsACopy = dayjs(dayjsA)
+  const dayjsBCopy = dayjs(dayjsB)
+  const result = dayjsA.duration(dayjsB)
+  expect(result.year).toBe(0)
+  expect(result.month).toBe(0)
+  expect(result.day).toBe(1)
+  expect(result.hour).toBe(0)
+  expect(result.minute).toBe(0)
+  expect(result.second).toBe(0)
+  expect(result.millisecond).toBe(0)
+  expect(+dayjsA).toEqual(+dayjsACopy, 'duration should not change moment')
+  expect(+dayjsB).toEqual(+dayjsBCopy, 'duration should not change moment')
+})
+
+it('duration between dates, future date', () => {
+  const dayjsA = dayjs(new Date(2018, 3, 3, 4, 45, 45, 400))
+  const dayjsB = dayjs(new Date(2019, 4, 15, 11, 20, 34, 700))
+  const dayjsACopy = dayjs(dayjsA)
+  const dayjsBCopy = dayjs(dayjsB)
+  const result = dayjsA.duration(dayjsB)
+  expect(result.year).toBe(1)
+  expect(result.month).toBe(1)
+  expect(result.day).toBe(12)
+  expect(result.hour).toBe(6)
+  expect(result.minute).toBe(34)
+  expect(result.second).toBe(49)
+  expect(result.millisecond).toBe(300)
+  expect(+dayjsA).toEqual(+dayjsACopy, 'duration should not change moment')
+  expect(+dayjsB).toEqual(+dayjsBCopy, 'duration should not change moment')
+})
+
+it('duration between dates, past date', () => {
+  const dayjsA = dayjs(new Date(2019, 4, 15, 11, 20, 34, 700))
+  const dayjsB = dayjs(new Date(2018, 3, 3, 4, 45, 45, 400))
+  const dayjsACopy = dayjs(dayjsA)
+  const dayjsBCopy = dayjs(dayjsB)
+  const result = dayjsA.duration(dayjsB)
+  expect(result.year).toBe(-1)
+  expect(result.month).toBe(-1)
+  expect(result.day).toBe(-12)
+  expect(result.hour).toBe(-6)
+  expect(result.minute).toBe(-34)
+  expect(result.second).toBe(-49)
+  expect(result.millisecond).toBe(-300)
+  expect(+dayjsA).toEqual(+dayjsACopy, 'duration should not change moment')
+  expect(+dayjsB).toEqual(+dayjsBCopy, 'duration should not change moment')
+})
+
+it('duration between same dates', () => {
+  const dayjsA = dayjs(new Date(2019, 2, 27, 23, 59, 59, 800))
+  const dayjsB = dayjs(new Date(2019, 2, 27, 23, 59, 59, 800))
+  const dayjsACopy = dayjs(dayjsA)
+  const dayjsBCopy = dayjs(dayjsB)
+  const result = dayjsA.duration(dayjsB)
+  expect(result.year).toBe(0)
+  expect(result.month).toBe(0)
+  expect(result.day).toBe(0)
+  expect(result.hour).toBe(0)
+  expect(result.minute).toBe(0)
+  expect(result.second).toBe(0)
+  expect(result.millisecond).toBe(0)
+  expect(+dayjsA).toEqual(+dayjsACopy, 'duration should not change moment')
+  expect(+dayjsB).toEqual(+dayjsBCopy, 'duration should not change moment')
+})

types/plugin/duration.d.ts

@@ -0,0 +1,10 @@
+import { PluginFunc } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
+
+declare module 'dayjs' {
+  interface Dayjs {
+    duration(input: ConfigType): any
+  }
+}