Implement simple fromNow() API based on timeago.js

ReadMe.md

@@ -359,6 +359,16 @@ dayjs().diff(Dayjs, unit);
 dayjs().diff(dayjs(), 'years'); // 0
 ```
 
+#### fromNow
+
+* returns a String
+
+Get the time that has passed between two `Dayjs` object. inspired by [timeago.js](http://timefromNow.org/)
+
+```js
+dayjs().fromNow(Dayjs); //e.g 5 years fromNow, in 2 hours, just now, 6 minutes fromNow, in 10 seconds...
+```
+
 #### Unix Timestamp (milliseconds)
 
 * returns a Number

package.json

@@ -42,8 +42,8 @@
     "pre-commit": "^1.2.2",
     "rollup": "^0.57.1",
     "rollup-plugin-babel": "^4.0.0-beta.4",
-    "rollup-plugin-uglify": "^3.0.0"
+    "rollup-plugin-uglify": "^3.0.0",
+    "timeago.js": "^3.0.2"
   },
-  "dependencies": {
-  }
+  "dependencies": {}
 }

src/index.js

@@ -282,6 +282,22 @@ class Dayjs {
     return float ? result : Utils.absFloor(result)
   }
 
+  fromNow(input) {
+    const P = [{ l: C.S, v: C.MILLISECONDS_A_SECOND }, { l: C.M, v: C.MILLISECONDS_A_SECOND * 60 },
+      { l: C.H, v: C.MILLISECONDS_A_HOUR }, { l: C.D, v: C.MILLISECONDS_A_DAY },
+      { l: C.W, v: C.MILLISECONDS_A_WEEK }, { l: C.M, v: C.MILLISECONDS_A_WEEK * 4 },
+      { l: C.Q, v: C.MILLISECONDS_A_WEEK * 12 }, { l: C.Y, v: C.MILLISECONDS_A_WEEK * 4 * 12 }]
+
+    const result = input.diff(this, `${C.MS}s`)
+    const resabs = Math.abs(result)
+    let out = ''
+    for (let i = 0; i < P.length; i += 1) {
+      if (resabs >= P[i].v) out = `${Utils.absFloor(resabs / P[i].v)} ${P[i].l}${(resabs / P[i].v !== 1) ? 's' : ''}`
+    }
+    if (!result) return 'just now'
+    return result > 0 ? `in ${out}` : `${out} ago`
+  }
+
   daysInMonth() {
     return this.endOf(C.M).$D
   }

test/display.test.js

@@ -1,5 +1,6 @@
 import moment from 'moment'
 import MockDate from 'mockdate'
+import timeago from 'timeago.js'
 import dayjs from '../src'
 
 beforeEach(() => {
@@ -111,44 +112,62 @@ describe('Difference', () => {
       expect(dayjsA.diff(dayjsC, unit, true)).toBe(momentA.diff(momentC, unit, true))
     })
   })
-})
+  it('fromNow -> in seconds, days, weeks, months, quarters, years ', () => {
+    const dayjsA = dayjs()
+    const dayjsB = dayjs().add(1000, 'days')
+    const dayjsC = dayjs().subtract(1000, 'days')
+    const dayjsD = dayjs().add(20, 'days')
+    const dayjsE = dayjs().subtract(30, 'seconds')
+    const dayjsF = dayjs().subtract(5, 'hours')
+    const dayjsG = dayjs().add(1001, 'days')
+
+    expect(dayjsA.fromNow(dayjsB)).toBe(timeago(dayjsA.toDate()).format(dayjsB.toDate()))
+    expect(dayjsA.fromNow(dayjsC)).toBe(timeago(dayjsA.toDate()).format(dayjsC.toDate()))
+    expect(dayjsA.fromNow(dayjsD)).toBe(timeago(dayjsA.toDate()).format(dayjsD.toDate()))
+    expect(dayjsA.fromNow(dayjsE)).toBe(timeago(dayjsA.toDate()).format(dayjsE.toDate()))
+    expect(dayjsA.fromNow(dayjsF)).toBe(timeago(dayjsA.toDate()).format(dayjsF.toDate()))
+    expect(dayjsB.fromNow(dayjsC)).toBe(timeago(dayjsB.toDate()).format(dayjsC.toDate()))
+    expect(dayjsB.fromNow(dayjsB)).toBe(timeago(dayjsB.toDate()).format(dayjsB.toDate()))
+    expect(dayjsG.fromNow(dayjsB)).toBe(timeago(dayjsG.toDate()).format(dayjsB.toDate()))
+  })
 
-it('Unix Timestamp (milliseconds)', () => {
-  expect(dayjs().valueOf()).toBe(moment().valueOf())
-})
+  it('Unix Timestamp (milliseconds)', () => {
+    expect(dayjs().valueOf()).toBe(moment().valueOf())
+  })
 
-it('Unix Timestamp (seconds)', () => {
-  expect(dayjs().unix()).toBe(moment().unix())
-})
+  it('Unix Timestamp (seconds)', () => {
+    expect(dayjs().unix()).toBe(moment().unix())
+  })
 
-it('Days in Month', () => {
-  expect(dayjs().daysInMonth()).toBe(moment().daysInMonth())
-  expect(dayjs('20140201').daysInMonth()).toBe(moment('20140201').daysInMonth())
-})
+  it('Days in Month', () => {
+    expect(dayjs().daysInMonth()).toBe(moment().daysInMonth())
+    expect(dayjs('20140201').daysInMonth()).toBe(moment('20140201').daysInMonth())
+  })
 
-it('As Javascript Date -> toDate', () => {
-  const base = dayjs()
-  const momentBase = moment()
-  const jsDate = base.toDate()
-  expect(jsDate).toEqual(momentBase.toDate())
-  expect(jsDate).toEqual(new Date())
+  it('As Javascript Date -> toDate', () => {
+    const base = dayjs()
+    const momentBase = moment()
+    const jsDate = base.toDate()
+    expect(jsDate).toEqual(momentBase.toDate())
+    expect(jsDate).toEqual(new Date())
 
-  jsDate.setFullYear(1970)
-  expect(jsDate.toUTCString()).not.toBe(base.toString())
-})
+    jsDate.setFullYear(1970)
+    expect(jsDate.toUTCString()).not.toBe(base.toString())
+  })
 
-it('As Array -> toArray', () => {
-  expect(dayjs().toArray()).toEqual(moment().toArray())
-})
+  it('As Array -> toArray', () => {
+    expect(dayjs().toArray()).toEqual(moment().toArray())
+  })
 
-it('As JSON -> toJSON', () => {
-  expect(dayjs().toJSON()).toBe(moment().toJSON())
-})
+  it('As JSON -> toJSON', () => {
+    expect(dayjs().toJSON()).toBe(moment().toJSON())
+  })
 
-it('As ISO 8601 String -> toISOString e.g. 2013-02-04T22:44:30.652Z', () => {
-  expect(dayjs().toISOString()).toBe(moment().toISOString())
-})
+  it('As ISO 8601 String -> toISOString e.g. 2013-02-04T22:44:30.652Z', () => {
+    expect(dayjs().toISOString()).toBe(moment().toISOString())
+  })
 
-it('As Object -> toObject', () => {
-  expect(dayjs().toObject()).toEqual(moment().toObject())
+  it('As Object -> toObject', () => {
+    expect(dayjs().toObject()).toEqual(moment().toObject())
+  })
 })