diff --git a/.babelrc b/babel.config.js
similarity index 87%
rename from .babelrc
rename to babel.config.js
index 6ae4011d2..a0291dac6 100644
--- a/.babelrc
+++ b/babel.config.js
@@ -1,20 +1,20 @@
-{
-  "env": {
-    "test": {
-      "presets": [
-        "@babel/preset-env"
-      ]
-    },
-    "build": {
-      "presets": [
-        [
-          "@babel/preset-env",
-          {
-            "modules": false,
-            "loose": true
-          }
-        ]
-      ]
-    }
-  }
-}
+module.exports = {
+  "env": {
+    "test": {
+      "presets": [
+        "@babel/preset-env"
+      ]
+    },
+    "build": {
+      "presets": [
+        [
+          "@babel/preset-env",
+          {
+            "modules": false,
+            "loose": true
+          }
+        ]
+      ]
+    }
+  }
+};
\ No newline at end of file
diff --git a/docs/en/Plugin.md b/docs/en/Plugin.md
index 7df564c7e..ea00de436 100644
--- a/docs/en/Plugin.md
+++ b/docs/en/Plugin.md
@@ -260,6 +260,9 @@ dayjs.extend(customParseFormat)
 
 dayjs('05/02/69 1:02:03 PM -05:00', 'MM/DD/YY H:mm:ss A Z')
 // Returns an instance containing '1969-05-02T18:02:03.000Z'
+
+dayjs('2018 Enero 15', { format: 'YYYY MMMM DD', locale: es })
+// Returns an instance containing '2018-01-15T00:00:00.000Z'
 ```
 
 #### List of all available format tokens
diff --git a/docs/es-es/Plugin.md b/docs/es-es/Plugin.md
index aede05fd1..5668155b9 100644
--- a/docs/es-es/Plugin.md
+++ b/docs/es-es/Plugin.md
@@ -247,6 +247,23 @@ dayjs.extend(quarterOfYear)
 dayjs('2010-04-01').quarter() // 2
 ```
 
+### CustomParseFormat
+ - CustomParseFormat extends `dayjs()` constructor to support custom formats of input strings.
+
+To escape characters, wrap them in square brackets (e.g. `[G]`). Punctuation symbols (-:/.()) do not need to be wrapped.
+
+```javascript
+import customParseFormat from 'dayjs/plugin/customParseFormat'
+
+dayjs.extend(customParseFormat)
+
+dayjs('05/02/69 1:02:03 PM -05:00', 'MM/DD/YY H:mm:ss A Z')
+// Returns an instance containing '1969-05-02T18:02:03.000Z'
+
+dayjs('2018 Enero 15', { format: 'YYYY MMMM DD', locale: es })
+// Returns an instance containing '2018-01-15T00:00:00.000Z'
+```
+
 #### List of all available format tokens
 
 | Format | Output  | Description                       |
diff --git a/docs/ja/Plugin.md b/docs/ja/Plugin.md
index 4be8f2e4f..981a29e27 100644
--- a/docs/ja/Plugin.md
+++ b/docs/ja/Plugin.md
@@ -269,6 +269,9 @@ dayjs.extend(customParseFormat)
 
 dayjs('05/02/69 1:02:03 PM -05:00', 'MM/DD/YY H:mm:ss A Z')
 // Returns an instance containing '1969-05-02T18:02:03.000Z'
+
+dayjs('2018 5月 15', { format: 'YYYY MMMM DD', locale: ja })
+// Returns an instance containing '2018-05-15T00:00:00.000Z'
 ```
 
 #### List of all available format tokens
diff --git a/docs/ko/Plugin.md b/docs/ko/Plugin.md
index cd96ff2d8..e203c811c 100644
--- a/docs/ko/Plugin.md
+++ b/docs/ko/Plugin.md
@@ -261,6 +261,9 @@ dayjs.extend(customParseFormat)
 
 dayjs('05/02/69 1:02:03 PM -05:00', 'MM/DD/YY H:mm:ss A Z')
 // Returns an instance containing '1969-05-02T18:02:03.000Z'
+
+dayjs('2018 5월 15', { format: 'YYYY MMMM DD', locale: ko })
+// Returns an instance containing '2018-05-15T00:00:00.000Z'
 ```
 
 #### List of all available format tokens
diff --git a/docs/pt-br/Plugin.md b/docs/pt-br/Plugin.md
index 0d6000488..04581f34c 100644
--- a/docs/pt-br/Plugin.md
+++ b/docs/pt-br/Plugin.md
@@ -260,6 +260,9 @@ dayjs.extend(customParseFormat)
 
 dayjs('05/02/69 1:02:03 PM -05:00', 'MM/DD/YY H:mm:ss A Z')
 // Returns an instance containing '1969-05-02T18:02:03.000Z'
+
+dayjs('2018 Fevereiro 15', { format: 'YYYY MMMM DD', locale: pt_br })
+// Returns an instance containing '2018-02-15T00:00:00.000Z'
 ```
 
 #### List of all available format tokens
diff --git a/docs/zh-cn/Plugin.md b/docs/zh-cn/Plugin.md
index 3ce2cd1c2..02938ab3e 100644
--- a/docs/zh-cn/Plugin.md
+++ b/docs/zh-cn/Plugin.md
@@ -260,6 +260,9 @@ dayjs.extend(customParseFormat)
 
 dayjs('05/02/69 1:02:03 PM -05:00', 'MM/DD/YY H:mm:ss A Z')
 // Returns an instance containing '1969-05-02T18:02:03.000Z'
+
+dayjs('2018 五月 15', { format: 'YYYY MMMM DD', locale: zh_cn })
+// Returns an instance containing '2018-05-15T00:00:00.000Z'
 ```
 
 #### List of all available format tokens
diff --git a/src/index.js b/src/index.js
index 2e2cdbdbc..e33a80a05 100644
--- a/src/index.js
+++ b/src/index.js
@@ -61,15 +61,16 @@ const parseDate = (date) => {
 
 class Dayjs {
   constructor(cfg) {
+    this.$L = this.$L || parseLocale(cfg.locale, null, true) || L
     this.parse(cfg) // for plugin
   }
 
   parse(cfg) {
     this.$d = parseDate(cfg.date)
-    this.init(cfg)
+    this.init()
   }
 
-  init(cfg) {
+  init() {
     const { $d } = this
     this.$y = $d.getFullYear()
     this.$M = $d.getMonth()
@@ -79,7 +80,6 @@ class Dayjs {
     this.$m = $d.getMinutes()
     this.$s = $d.getSeconds()
     this.$ms = $d.getMilliseconds()
-    this.$L = this.$L || parseLocale(cfg.locale, null, true) || L
   }
 
   // eslint-disable-next-line class-methods-use-this
diff --git a/src/plugin/customParseFormat/index.js b/src/plugin/customParseFormat/index.js
index ad639beb1..0d8e0acb0 100644
--- a/src/plugin/customParseFormat/index.js
+++ b/src/plugin/customParseFormat/index.js
@@ -1,4 +1,4 @@
-const formattingTokens = /(\[[^[]*\])|([-:/.()\s]+)|(A|a|YYYY|YY?|MM?|DD?|hh?|HH?|mm?|ss?|S{1,3}|z|ZZ?)/g
+const formattingTokens = /(\[[^[]*\])|([-:/.()\s]+)|(A|a|YYYY|YY?|MM?M?M?|DD?|hh?|HH?|mm?|ss?|S{1,3}|z|ZZ?)/g
 
 const match1 = /\d/ // 0 - 9
 const match2 = /\d\d/ // 00 - 99
@@ -9,6 +9,9 @@ const matchUpperCaseAMPM = /[AP]M/
 const matchLowerCaseAMPM = /[ap]m/
 const matchSigned = /[+-]?\d+/ // -inf - inf
 const matchOffset = /[+-]\d\d:?\d\d/ // +00:00 -00:00 +0000 or -0000
+const matchWord = /\d*[^\s\d]+/ // Word
+
+let locale
 
 function offsetFromString(string) {
   const parts = string.match(/([+-]|\d\d)/g)
@@ -55,6 +58,24 @@ const expressions = {
   DD: [match2, addInput('day')],
   M: [match1to2, addInput('month')],
   MM: [match2, addInput('month')],
+  MMM: [matchWord, function (input) {
+    const { months, monthsShort } = locale
+    const matchIndex = monthsShort
+      ? monthsShort.findIndex(month => month === input)
+      : months.findIndex(month => month.substr(0, 3) === input)
+    if (matchIndex < 0) {
+      throw new Error()
+    }
+    this.month = matchIndex + 1
+  }],
+  MMMM: [matchWord, function (input) {
+    const { months } = locale
+    const matchIndex = months.indexOf(input)
+    if (matchIndex < 0) {
+      throw new Error()
+    }
+    this.month = matchIndex + 1
+  }],
   Y: [matchSigned, addInput('year')],
   YY: [match2, function (input) {
     input = +input
@@ -144,6 +165,7 @@ export default (o, C) => {
   proto.parse = function (cfg) {
     const { date: input, format } = cfg
     if (format) {
+      locale = this.$locale()
       this.$d = parseFormattedInput(input, format)
       this.init(cfg)
     } else {
diff --git a/test/plugin/customParseFormat.test.js b/test/plugin/customParseFormat.test.js
index e26cbea30..b278462f9 100644
--- a/test/plugin/customParseFormat.test.js
+++ b/test/plugin/customParseFormat.test.js
@@ -2,6 +2,7 @@ import MockDate from 'mockdate'
 import moment from 'moment'
 import dayjs from '../../src'
 import customParseFormat from '../../src/plugin/customParseFormat'
+import uk from '../../src/locale/uk'
 
 dayjs.extend(customParseFormat)
 
@@ -84,3 +85,56 @@ it('fails with an invalid format', () => {
   expect(dayjs(input, format).format().toLowerCase())
     .toBe(moment(input, format).format().toLowerCase())
 })
+
+it('parse month from string', () => {
+  const input = '2018 February 03'
+  const format = 'YYYY MMMM DD'
+  expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parse month from short string', () => {
+  const input = '2018 Feb 03'
+  const format = 'YYYY MMM DD'
+  expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parse month from string with locale in config', () => {
+  const input = '2018 лютий 03'
+  const format = 'YYYY MMMM DD'
+
+  expect(dayjs(input, { format, locale: uk }).valueOf()).toBe(moment(input, format, 'uk').valueOf())
+})
+
+it('parse month from short string with locale in config', () => {
+  const input = '2018 трав 03'
+  const format = 'YYYY MMM DD'
+  expect(dayjs(input, { format, locale: uk }).valueOf()).toBe(moment(input, format, 'uk').valueOf())
+})
+
+it('return Invalid Date when parse corrupt string', () => {
+  const input = '2018 Turnip 03'
+  const format = 'YYYY MMMM DD'
+  expect(dayjs(input, format).format()).toBe('Invalid Date')
+})
+
+it('return Invalid Date when parse corrupt short string', () => {
+  const input = '2018 Dog 03'
+  const format = 'YYYY MMM DD'
+  expect(dayjs(input, format).format()).toBe('Invalid Date')
+})
+
+it('correctly parse month from string after changing locale globally', () => {
+  const input = '2018 лютий 03'
+  const format = 'YYYY MMMM DD'
+
+  const dayjsLocale = dayjs().$locale()
+  const momentLocale = moment.locale()
+  try {
+    dayjs.locale(uk)
+    moment.locale('uk')
+    expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
+  } finally {
+    dayjs.locale(dayjsLocale)
+    moment.locale(momentLocale)
+  }
+})