diff --git a/src/plugin/localeData/index.js b/src/plugin/localeData/index.js
--- a/src/plugin/localeData/index.js
+++ b/src/plugin/localeData/index.js
@@ -17,7 +17,8 @@ export default (o, c, dayjs) => { // locale needed later
       weekdaysMin: instance =>
         (instance ? instance.format('dd') : getShort(this, 'weekdaysMin', 'weekdays', 2)),
       weekdaysShort: instance =>
-        (instance ? instance.format('ddd') : getShort(this, 'weekdaysShort', 'weekdays', 3))
+        (instance ? instance.format('ddd') : getShort(this, 'weekdaysShort', 'weekdays', 3)),
+      longDateFormat: format => this.$locale().formats[format]
     }
   }
   proto.localeData = function () {

diff --git a/test/plugin/localeData.test.js b/test/plugin/localeData.test.js
--- a/test/plugin/localeData.test.js
+++ b/test/plugin/localeData.test.js
@@ -2,8 +2,10 @@ import MockDate from 'mockdate'
 import moment from 'moment'
 import dayjs from '../../src'
 import localeData from '../../src/plugin/localeData'
+import localizedFormat from '../../src/plugin/localizedFormat'
 import '../../src/locale/zh-cn'
 
+dayjs.extend(localizedFormat)
 dayjs.extend(localeData)
 
 beforeEach(() => {
@@ -14,7 +16,7 @@ afterEach(() => {
   MockDate.reset()
 })
 
-it('instance localeData', () => {
+it('Instance localeData', () => {
   const d = dayjs()
   const m = moment()
   const dayjsLocaleData = dayjs().localeData()
@@ -28,9 +30,14 @@ it('instance localeData', () => {
   expect(dayjsLocaleData.weekdaysMin()).toEqual(momentLocaleData.weekdaysMin())
   expect(dayjsLocaleData.weekdaysShort(d)).toBe(momentLocaleData.weekdaysShort(m))
   expect(dayjsLocaleData.weekdaysShort()).toEqual(momentLocaleData.weekdaysShort())
+  const longDateFormats = ['LT', 'LTS', 'L', 'LL', 'LLL', 'LLLL']
+  longDateFormats.forEach((f) => {
+    expect(dayjsLocaleData.longDateFormat(f)).toEqual(momentLocaleData.longDateFormat(f))
+  })
 })
 
-it('global localeData', () => {
+
+it('Global localeData', () => {
   dayjs.locale('zh-cn')
   moment.locale('zh-cn')
   let dayjsLocaleData = dayjs.localeData()

How to get the locale format?
What is the equivalent of this moment code?

`moment.localeData().longDateFormat('L')`

We will add it later to LocaleData plugin   https://github.com/iamkun/dayjs/blob/dev/src/plugin/localeData/index.js

You can get it in this way at the present
```
var dayjs = require("dayjs")
var LocalizedFormat = require( 'dayjs/plugin/localizedFormat')

dayjs.extend(LocalizedFormat)

console.log(dayjs.Ls.en.formats.L)
```
Thanks!
@iamkun has this been added? currently trying to use react-dates from airbnb with dayjs. And it uses this longDateFormat method :/
https://github.com/airbnb/react-dates/issues/1294
It's not added at the moment
Sorry for the delay, I'll add it today 😁 
test/timezone.test.js(1) test/timezone.test.js(2) test/timezone.test.js(3) test/timezone.test.js(4)
test/plugin/localeData.test.js