feat: Recognize localizable format L, LT and LTS in custom parse formats

* Translate localizable formats for date parsing as well. Only for the numeric format tokens for the time being.
* Expose the function getLocale via Utils to get access to te global default locale.

docs/en/Plugin.md

@@ -229,6 +229,8 @@ dayjs('05/02/69 1:02:03 PM -05:00', { format: 'MM/DD/YY H:mm:ss A Z' })
 | `A`    | AM PM            | Post or ante meridiem, upper-case |
 | `a`    | am pm            | Post or ante meridiem, lower-case |
 
+If the plugin [LocalizableFormat](#localizableformat) is installed, format tokens "L", "LT" and "LTS" can be used too. They will be translated to the concrete tokens above using the `locale` parameter passed to the `dayjs` constructor, or using the global `dayjs` locale.
+
 ### TimeZone
  - TimeZone extends `dayjs()` and `dayjs().format` APIs to support the most important usage scenatrios - parsing from a specific time zone and formatting in other time zone.
 

src/index.js

@@ -27,6 +27,22 @@ const parseLocale = (preset, object, isLocal) => {
   return l
 }
 
+const getLocale = (locale) => {
+  if (typeof locale === 'string') {
+    // Get locale by its name.
+    return Ls[locale]
+  }
+  if (locale) {
+    // Register a locale object by its name.
+    const { name } = locale
+    Ls[name] = locale
+  } else {
+    // Get the de4fault locale.
+    locale = Ls[L]
+  }
+  return locale
+}
+
 const dayjs = (date, c) => {
   if (isDayjs(date)) {
     if (c) {
@@ -48,6 +64,7 @@ const wrapper = (date, instance, cloneDate) =>
 
 const Utils = U // for plugin use
 Utils.parseLocale = parseLocale
+Utils.getLocale = getLocale
 Utils.isDayjs = isDayjs
 Utils.wrapper = wrapper
 

src/plugin/localizableFormat/index.js

@@ -1,7 +1,9 @@
 import { FORMAT_DEFAULT } from '../../constant'
+import Utils from '../../utils'
 
 export default (o, c, d) => {
   const proto = c.prototype
+  const oldParse = proto.parse
   const oldFormat = proto.format
   const englishFormats = {
     LTS: 'h:mm:ss A',
@@ -12,6 +14,16 @@ export default (o, c, d) => {
     LLLL: 'dddd, MMMM D, YYYY h:mm A'
   }
   d.en.formats = englishFormats
+  proto.parse = function (cfg) {
+    const format = cfg && cfg.format
+    if (format) {
+      const locale = Utils.getLocale(cfg.locale)
+      const formats = locale.formats || {}
+      cfg.format = format.replace(/LTS|LT|L/g, match =>
+        formats[match] || englishFormats[match])
+    }
+    oldParse.call(this, cfg)
+  }
   proto.format = function (formatStr) {
     const locale = this.$locale()
     const formats = locale.formats || {}

test/plugin/localizableCustomParseFormat.test.js

@@ -0,0 +1,70 @@
+import MockDate from 'mockdate'
+import moment from 'moment'
+import dayjs from '../../src'
+import es from '../../src/locale/es'
+import customParseFormat from '../../src/plugin/customParseFormat'
+import localizableFormat from '../../src/plugin/localizableFormat'
+
+dayjs.extend(customParseFormat)
+dayjs.extend(localizableFormat)
+
+beforeEach(() => {
+  MockDate.set(new Date())
+})
+
+afterEach(() => {
+  MockDate.reset()
+})
+
+it('does not break the built-in parsing', () => {
+  const input = '2018-05-02 01:02:03.004'
+  expect(dayjs(input).valueOf()).toBe(moment(input).valueOf())
+})
+
+it('does not break the non-localizable parsing', () => {
+  const input = '2.5.18'
+  const format = 'D.M.YY'
+  expect(dayjs(input, { format }).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parses English L', () => {
+  const input = '05/02/2018'
+  const format = 'L'
+  expect(dayjs(input, { format }).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parses English LT', () => {
+  const input = '05/02/2018 12:31 PM'
+  const format = 'L LT'
+  expect(dayjs(input, { format }).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parses English LTS', () => {
+  const input = '05/02/2018 12:31:32 PM'
+  const format = 'L LTS'
+  expect(dayjs(input, { format }).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parses Spanish L with locale es object', () => {
+  const input = '02/05/2018'
+  const format = 'L'
+  const date = new Date(2018, 4, 2)
+  expect(dayjs(input, { format, locale: es }).valueOf()).toBe(date.valueOf())
+})
+
+it('parses Spanish LT with locale es string', () => {
+  const input = '02/05/2018 12:31'
+  const format = 'L LT'
+  const date = new Date(2018, 4, 2, 12, 31)
+  expect(dayjs(input, { format, locale: 'es' }).valueOf()).toBe(date.valueOf())
+})
+
+it('parses Spanish LTS with the global locale', () => {
+  const input = '02/05/2018 12:31:32'
+  const format = 'L LTS'
+  const expectedDate = new Date(2018, 4, 2, 12, 31, 32)
+  dayjs.locale('es');
+  const actualDate = dayjs(input, { format })
+  dayjs.locale('en')
+  expect(actualDate.valueOf()).toBe(expectedDate.valueOf())
+})