feat: add a new option fallbackRootWithEmptyString

decls/i18n.js

@@ -89,6 +89,7 @@ declare type I18nOptions = {
   modifiers?: Modifiers,
   root?: I18n, // for internal
   fallbackRoot?: boolean,
+  fallbackRootWithEmptyString?: boolean,
   formatFallbackMessages?: boolean,
   sync?: boolean,
   silentTranslationWarn?: boolean | RegExp,

gitbook/en/api.md

@@ -235,6 +235,20 @@ You can specify the below some options of `I18nOptions` constructor options of [
 
   If `false`, it's warned, and is returned the key.
 
+#### fallbackRootWithEmptyString
+
+> :new: 8.26+
+
+- **Type:** `Boolean`
+
+- **Default:** `true`
+
+  In the component localization, whether to fall back to root level (global) localization when local message is an empty string.
+
+  Please note the default behavior in vue-i18n 9.x is to not falling back to root for local message that is empty string.
+
+  If `false`, the empty local message will not fall back to root and will be kept as empty string.
+
 #### sync
 
 - **Type:** `Boolean`

src/index.js

@@ -48,6 +48,7 @@ export default class VueI18n {
   _root: any
   _sync: boolean
   _fallbackRoot: boolean
+  _fallbackRootWithEmptyString: boolean
   _localeChainCache: { [key: string]: Array<Locale>; }
   _missing: ?MissingHandler
   _exist: Function
@@ -95,6 +96,9 @@ export default class VueI18n {
     this._fallbackRoot = options.fallbackRoot === undefined
       ? true
       : !!options.fallbackRoot
+    this._fallbackRootWithEmptyString = options.fallbackRootWithEmptyString === undefined
+      ? true
+      : !!options.fallbackRootWithEmptyString
     this._formatFallbackMessages = options.formatFallbackMessages === undefined
       ? false
       : !!options.formatFallbackMessages
@@ -379,7 +383,7 @@ export default class VueI18n {
   }
 
   _isFallbackRoot (val: any): boolean {
-    return !val && !isNull(this._root) && this._fallbackRoot
+    return (this._fallbackRootWithEmptyString? !val : isNull(val)) && !isNull(this._root) && this._fallbackRoot
   }
 
   _isSilentFallbackWarn (key: Path): boolean {
@@ -461,7 +465,7 @@ export default class VueI18n {
     // We are going to replace each of
     // them with its translation
     const matches: any = ret.match(linkKeyMatcher)
-    
+
     // eslint-disable-next-line no-autofix/prefer-const
     for (let idx in matches) {
       // ie compatible: filter custom array

test/unit/component.test.js

@@ -137,4 +137,131 @@ describe('component translation', () => {
       vm.$destroy()
     }).then(done)
   })
+
+  it('fallbackRootWithEmptyString default to be true', done => {
+    const el = document.createElement('div')
+    let vm = new Vue({
+      i18n,
+      components: {
+        child: { // translation with component
+          i18n: {
+            locale: 'en-US',
+            sync: false,
+            messages: {
+              'en-US': {
+                who: 'child'
+              },
+              'ja-JP': {
+                who: '子',
+              }
+            },
+          },
+          components: {
+            'sub-child': { // translation with root
+              i18n: {
+                locale: 'ja-JP',
+                sync: false,
+                messages: {
+                  'en-US': {
+                    who: 'sub-child'
+                  },
+                  'ja-JP': {
+                    who: ''
+                  }
+                },
+                sharedMessages: { // shared messages for child1 component
+                  'en-US': { foo: { bar: 'bar' } },
+                  'ja-JP': { foo: { bar: 'バー' } }
+                }
+              },
+              render (h) {
+                return h('div', {}, [
+                  h('p', { ref: 'who' }, [this.$t('who')])
+                ])
+              }
+            }
+          },
+          render (h) {
+            return h('div', {}, [
+              h('p', { ref: 'who' }, [this.$t('who')]),
+              h('sub-child', { ref: 'sub-child' })
+            ])
+          }
+        },
+      },
+      render (h) {
+        return h('div', {}, [
+          h('p', { ref: 'who' }, [this.$t('who')]),
+          h('child', { ref: 'child' }),
+        ])
+      }
+    }).$mount(el)
+    Vue.nextTick().then(() => {
+      assert.strictEqual(vm.$refs.child.$refs['sub-child'].$refs.who.textContent, 'ルート')
+    }).then(done)
+  })
+
+  it('fallbackRootWithEmptyString should work when set to false', done => {
+    const el = document.createElement('div')
+    let vm = new Vue({
+      i18n,
+      components: {
+        child: { // translation with component
+          i18n: {
+            locale: 'en-US',
+            sync: false,
+            messages: {
+              'en-US': {
+                who: 'child'
+              },
+              'ja-JP': {
+                who: '子',
+              }
+            },
+          },
+          components: {
+            'sub-child': { // translation with root
+              i18n: {
+                locale: 'ja-JP',
+                sync: false,
+                fallbackRootWithEmptyString: false,
+                messages: {
+                  'en-US': {
+                    who: 'sub-child'
+                  },
+                  'ja-JP': {
+                    who: ''
+                  }
+                },
+                sharedMessages: { // shared messages for child1 component
+                  'en-US': { foo: { bar: 'bar' } },
+                  'ja-JP': { foo: { bar: 'バー' } }
+                }
+              },
+              render (h) {
+                return h('div', {}, [
+                  h('p', { ref: 'who' }, [this.$t('who')])
+                ])
+              }
+            }
+          },
+          render (h) {
+            return h('div', {}, [
+              h('p', { ref: 'who' }, [this.$t('who')]),
+              h('sub-child', { ref: 'sub-child' })
+            ])
+          }
+        },
+      },
+      render (h) {
+        return h('div', {}, [
+          h('p', { ref: 'who' }, [this.$t('who')]),
+          h('child', { ref: 'child' }),
+        ])
+      }
+    }).$mount(el)
+    Vue.nextTick().then(() => {
+      assert.strictEqual(vm.$refs.child.$refs['sub-child'].$refs.who.textContent, '')
+    }).then(done)
+  })
 })

types/index.d.ts

@@ -145,6 +145,7 @@ declare namespace VueI18n {
     modifiers?: Modifiers,
     missing?: MissingHandler;
     fallbackRoot?: boolean;
+    fallbackRootWithEmptyString?: boolean,
     formatFallbackMessages?: boolean;
     sync?: boolean;
     silentTranslationWarn?: boolean | RegExp;
@@ -240,7 +241,7 @@ declare class VueI18n {
   te(key: VueI18n.Path, locale?: VueI18n.Locale): boolean;
   d(value: number | Date, key?: VueI18n.Path, locale?: VueI18n.Locale): VueI18n.DateTimeFormatResult;
   d(value: number | Date, args?: { [key: string]: string }): VueI18n.DateTimeFormatResult;
-  d(value: number | Date, options?: VueI18n.DateTimeFormatOptions): VueI18n.DateTimeFormatResult;  
+  d(value: number | Date, options?: VueI18n.DateTimeFormatOptions): VueI18n.DateTimeFormatResult;
   n(value: number, key?: VueI18n.Path, locale?: VueI18n.Locale): VueI18n.NumberFormatResult;
   n(value: number, args?: { [key: string]: string }): VueI18n.NumberFormatResult;
   n(value: number, options?: VueI18n.NumberFormatOptions, locale?: VueI18n.Locale): VueI18n.NumberFormatResult;

vuepress/api/README.md

@@ -272,6 +272,20 @@ In the component localization, whether to fall back to root level (global) local
 
 If `false`, it's warned, and is returned the key.
 
+#### fallbackRootWithEmptyString
+
+> :new: 8.26+
+
+- **Type:** `Boolean`
+
+- **Default:** `true`
+
+  In the component localization, whether to fall back to root level (global) localization when local message is an empty string.
+
+  Please note the default behavior in vue-i18n 9.x is to not falling back to root for local message that is empty string.
+
+  If `false`, the empty local message will not fall back to root and will be kept as empty string.
+
 #### sync
 
   * **Type:** `Boolean`

vuepress/pt/api/README.md

@@ -272,6 +272,20 @@ Ao usar a localização em componentes, determina se deve consultar a localizaç
 
 Se definido como `false`, um aviso será lançado e uma chave retornada.
 
+#### fallbackRootWithEmptyString
+
+> :new: Adicionado na versão 8.26+
+
+* **Tipo:** `Boolean`
+
+* **Padrão:** `true`
+
+Na localização do componente, se deve retornar à localização de nível raiz (global) quando a mensagem local for uma string vazia.
+
+Por favor, note que o comportamento padrão no vue-i18n 9.x é não voltar ao root para a mensagem local que é uma string vazia.
+
+Se for `false`, a mensagem local vazia não retornará ao root e será mantida como string vazia.
+
 #### sync
 
 * **Tipo:** `Boolean`

vuepress/ru/api/README.md

@@ -272,6 +272,20 @@ sidebar: auto
 
 При значении `false` будет выбрасываться предупреждение и возвращаться ключ.
 
+#### fallbackRootWithEmptyString
+
+> :new: Добавлено в версии 8.26+
+
+* **Тип:** `Boolean`
+
+* **По умолчанию:** `true`
+
+В локализации компонента укажите, следует ли вернуться к локализации корневого уровня (глобальной), если локальное сообщение представляет собой пустую строку.
+
+Обратите внимание, что поведение по умолчанию в vue-i18n 9.x заключается в том, чтобы не возвращаться к корневому каталогу для локального сообщения, которое является пустой строкой.
+
+Если `false`, пустое локальное сообщение не будет возвращено в корень и будет храниться как пустая строка.
+
 #### sync
 
 * **Тип:** `Boolean`

vuepress/zh/api/README.md

@@ -254,6 +254,20 @@ vue-i18n 版本
 
 如果为 `false`，则会发出警告，并返回 key。
 
+#### fallbackRootWithEmptyString
+
+> :new: 8.26+ 新增
+
+  * **Type:** `Boolean`
+
+  * **Default:** `true`
+
+在组件本地化中，当本地化文本为空字符串时，是否回退到根级别 (全局) 本地化。
+
+请注意，vue-i18n 9.x版本的默认行为是对空字符串本地化文本进行回退到根级别本地化。
+
+如果为`false`，则空的本地化文本将不会回退到根目录，并将保留为空字符串。
+
 #### sync
 
   * **类型：**`Boolean`