Add fallback formatting

src/index.js

@@ -42,6 +42,7 @@ export default class VueI18n {
   _missing: ?MissingHandler
   _exist: Function
   _silentTranslationWarn: boolean
+  _formatFallbackMessages: boolean
   _silentFallbackWarn: boolean
   _dateTimeFormatters: Object
   _numberFormatters: Object
@@ -79,6 +80,9 @@ export default class VueI18n {
     this._silentTranslationWarn = options.silentTranslationWarn === undefined
       ? false
       : !!options.silentTranslationWarn
+    this._formatFallbackMessages = options.formatFallbackMessages === undefined
+      ? false
+      : !!options.formatFallbackMessages
     this._silentFallbackWarn = options.silentFallbackWarn === undefined
       ? false
       : !!options.silentFallbackWarn
@@ -274,6 +278,13 @@ export default class VueI18n {
         )
       }
     }
+
+    if (this._formatFallbackMessages) {
+      const parsedArgs = parseArgs(...values)
+
+      return this._render(key, 'string', parsedArgs.params, key)
+    }
+
     return key
   }
 

test/unit/basic.test.js

@@ -161,6 +161,60 @@ describe('basic', () => {
       })
     })
 
+    describe('format arguments of fallback', () => {
+      describe('if activated', () => {
+        describe('named', () => {
+          it('should return replaced string', () => {
+            i18n = new VueI18n({
+              locale: 'en',
+              fallbackLocale: 'en',
+              formatFallbackMessages: true
+            })
+
+            assert.strictEqual(
+              i18n.t('Hello {name}, how are you?', { name: 'kazupon' }),
+              'Hello kazupon, how are you?'
+            )
+          })
+        })
+
+        describe('list', () => {
+          it('should return replaced string', () => {
+            i18n = new VueI18n({
+              locale: 'en',
+              fallbackLocale: 'en',
+              formatFallbackMessages: true
+            })
+
+            assert.strictEqual(
+              i18n.t('Hello {0}, how are you?', ['kazupon']),
+              'Hello kazupon, how are you?'
+            )
+          })
+        })
+      })
+
+      describe('if not activated', () => {
+        describe('named', () => {
+          it('should not return replaced string', () => {
+            assert.strictEqual(
+              i18n.t('Hello {name}, how are you?', { name: 'kazupon' }),
+              'Hello {name}, how are you?'
+            )
+          })
+        })
+
+        describe('list', () => {
+          it('should not return replaced string', () => {
+            assert.strictEqual(
+              i18n.t('Hello {0}, how are you?', ['kazupon']),
+              'Hello {0}, how are you?'
+            )
+          })
+        })
+      })
+    })
+
     describe('locale argument', () => {
       it('should return empty string', () => {
         assert.strictEqual(i18n.t('message.hello', 'ja'), messages.ja.message.hello)