⭐ new(config): translation miss capturing configration

Closes #54

src/config.js

@@ -1,6 +1,7 @@
 import { getWatcher, getDep } from './observer'
 
 let fallback // fallback lang
+let missingHandler = null // missing handler
 
 export default function (Vue, langVM, lang) {
   const { bind } = Vue.util
@@ -35,4 +36,12 @@ export default function (Vue, langVM, lang) {
     get: () => { return fallback },
     set: val => { fallback = val }
   })
+
+  // define Vue.config.missingHandler configration
+  Object.defineProperty(Vue.config, 'missingHandler', {
+    enumerable: true,
+    configurable: true,
+    get: () => { return missingHandler },
+    set: val => { missingHandler = val }
+  })
 }

src/extend.js

@@ -81,11 +81,12 @@ export default function (Vue) {
   }
 
 
-  function warnDefault (key) {
+  function warnDefault (lang, key, vm) {
     if (process.env.NODE_ENV !== 'production') {
       warn('Cannot translate the value of keypath "' + key + '". '
         + 'Use the value of keypath as default')
     }
+    Vue.config.missingHandler && Vue.config.missingHandler.apply(null, [lang, key, vm])
     return key
   }
 
@@ -117,7 +118,7 @@ export default function (Vue) {
     if (!key) { return '' }
     const { lang, fallback, params } = parseArgs(...args)
     return translate(getAssetLocale, lang, fallback, key, params)
-      || warnDefault(key)
+      || warnDefault(lang, key, null)
   }
 
   /**
@@ -153,7 +154,7 @@ export default function (Vue) {
       if (res) { return res }
     }
     return translate(getAssetLocale, lang, fallback, key, params)
-      || warnDefault(key)
+      || warnDefault(lang, key, this)
   }
 
   /**

test/specs/index.js

@@ -10,4 +10,5 @@ Vue.use(plugin)
 require('./i18n')
 require('./asset')
 require('./component')
+require('./missing')
 require('./issues')

test/specs/missing.js

@@ -0,0 +1,44 @@
+import assert from 'power-assert'
+import Vue from 'vue'
+
+
+describe('missing', () => {
+  let lang
+  beforeEach(() => {
+    lang = Vue.config.lang
+    Vue.config.lang = 'en'
+  })
+
+  afterEach(done => {
+    Vue.config.lang = lang
+    Vue.config.missingHandler = null
+    Vue.nextTick(done)
+  })
+
+  describe('global', () => {
+    it('should be handled translate missing', done => {
+      Vue.config.missingHandler = (lang, key, vm) => {
+        assert.equal('en', lang)
+        assert.equal('foo.bar.buz', key)
+        assert(vm === null)
+        done()
+      }
+
+      Vue.t('foo.bar.buz')
+    })
+  })
+
+  describe('instance', () => {
+    it('should be handled translate missing', done => {
+      const vm = new Vue()
+      Vue.config.missingHandler = (lang, key, instance) => {
+        assert.equal('en', lang)
+        assert.equal('foo.bar.buz', key)
+        assert(vm === instance)
+        done()
+      }
+
+      vm.$t('foo.bar.buz')
+    })
+  })
+})