improvement(extend): support translate empty string (#86) by @QingWei-Li

src/asset.js

@@ -8,7 +8,7 @@ export default function (Vue, langVM) {
    * @param {Object | Function | Promise} definition
    * @param {Function} cb
    */
-  
+
   Vue.locale = (id, definition, cb) => {
     if (definition === undefined) { // gettter
       return langVM.locales[id]

src/extend.js

@@ -1,7 +1,7 @@
 import warn from './warn'
 import Format from './format'
 import Path from './path'
-
+import { isNil } from './util'
 
 /**
  * extend
@@ -40,8 +40,9 @@ export default function (Vue) {
   function interpolate (locale, key, args) {
     if (!locale) { return null }
 
-    let val = getValue(locale, key) || locale[key]
-    if (!val) { return null }
+    let val = getValue(locale, key)
+    if (isNil(val)) val = locale[key]
+    if (isNil(val)) { return null }
 
     // Check for the existance of links within the translated string
     if (val.indexOf('@:') >= 0) {
@@ -70,10 +71,10 @@ export default function (Vue) {
   function translate (getter, lang, fallback, key, params) {
     let res = null
     res = interpolate(getter(lang), key, params)
-    if (res) { return res }
+    if (!isNil(res)) { return res }
 
     res = interpolate(getter(fallback), key, params)
-    if (res) {
+    if (!isNil(res)) {
       if (process.env.NODE_ENV !== 'production') {
         warn('Fall back to translate the keypath "' + key + '" with "'
           + fallback + '" language.')
@@ -85,7 +86,8 @@ export default function (Vue) {
   }
 
 
-  function warnDefault (lang, key, vm) {
+  function warnDefault (lang, key, vm, result) {
+    if (!isNil(result)) { return result }
     if (process.env.NODE_ENV !== 'production') {
       warn('Cannot translate the value of keypath "' + key + '". '
         + 'Use the value of keypath as default')
@@ -134,8 +136,7 @@ export default function (Vue) {
   Vue.t = (key, ...args) => {
     if (!key) { return '' }
     const { lang, fallback, params } = parseArgs(...args)
-    return translate(getAssetLocale, lang, fallback, key, params)
-      || warnDefault(lang, key, null)
+    return warnDefault(lang, key, null, translate(getAssetLocale, lang, fallback, key, params))
   }
 
   /**
@@ -169,8 +170,7 @@ export default function (Vue) {
       )
       if (res) { return res }
     }
-    return translate(getAssetLocale, lang, fallback, key, params)
-      || warnDefault(lang, key, this)
+    return warnDefault(lang, key, this, translate(getAssetLocale, lang, fallback, key, params))
   }
 
   /**

src/format.js

@@ -1,6 +1,8 @@
+import { isNil } from './util'
+
 /**
  *  String format template
- *  - Inspired:  
+ *  - Inspired:
  *    https://github.com/Matt-Esch/string-template/index.js
  */
 
@@ -12,7 +14,7 @@ export default function (Vue) {
 
   /**
    * template
-   *  
+   *
    * @param {String} string
    * @param {Array} ...args
    * @return {String}
@@ -37,7 +39,7 @@ export default function (Vue) {
         return i
       } else {
         result = hasOwn(args, i) ? args[i] : match
-        if (result === null || result === undefined) {
+        if (isNil(result)) {
           return ''
         }
 

src/util.js

@@ -0,0 +1,3 @@
+export function isNil (val) {
+  return val === null || val === undefined
+}

test/specs/fixture/locales.js

@@ -3,6 +3,7 @@ export default {
     message: {
       hello: 'the world',
       hoge: 'hoge',
+      empty: '',
       format: {
         named: 'Hello {name}, how are you?',
         list: 'Hello {0}, how are you?'
@@ -41,6 +42,7 @@ export default {
     message: {
       hello: 'ザ・ワールド',
       hoge: 'ほげ',
+      empty: '',
       format: {
         named: 'こんにちは {name}, ごきげんいかが？',
         list: 'こんにちは {0}, ごきげんいかが？'

test/specs/i18n.js

@@ -21,6 +21,12 @@ describe('i18n', () => {
       })
     })
 
+    describe('empty string', () => {
+      it('should support empty string', () => {
+        assert.equal(Vue.t('message.empty'), locales.en.message.empty)
+      })
+    })
+
     describe('linked translation', () => {
       it('should translate simple link', () => {
         assert.equal(Vue.t('message.link'), locales.en.message.hello)