Add onComponentInstanceCreated constructor option

decls/i18n.js

@@ -45,13 +45,14 @@ declare type NumberFormatOptions = {
 };
 declare type NumberFormat = { [key: string]: NumberFormatOptions };
 declare type NumberFormats = { [key: Locale]: NumberFormat };
-declare type Modifiers = { [key: string]: (str : string) => string };
+declare type Modifiers = { [key: string]: (str: string) => string };
 
 declare type TranslateResult = string | LocaleMessages;
 declare type DateTimeFormatResult = string;
 declare type NumberFormatResult = string;
 declare type MissingHandler = (locale: Locale, key: Path, vm?: any) => string | void;
 declare type PostTranslationHandler = (str: string, key?: string) => string;
+declare type ComponentInstanceCreatedListener = (newI18n: I18n, rootI18n: I18n) => void;
 
 declare type FormattedNumberPartType = 'currency' | 'decimal' | 'fraction' | 'group' | 'infinity' | 'integer' | 'literal' | 'minusSign' | 'nan' | 'plusSign' | 'percentSign';
 declare type FormattedNumberPart = {
@@ -84,6 +85,7 @@ declare type I18nOptions = {
   warnHtmlInMessage?: WarnHtmlInMessageLevel,
   sharedMessages?: LocaleMessage,
   postTranslation?: PostTranslationHandler,
+  componentInstanceCreatedListener?: ComponentInstanceCreatedListener,
 };
 
 declare type IntlAvailability = {

src/index.js

@@ -55,6 +55,7 @@ export default class VueI18n {
   _numberFormatters: Object
   _path: I18nPath
   _dataListeners: Array<any>
+  _componentInstanceCreatedListener: ?ComponentInstanceCreatedListener
   _preserveDirectiveContent: boolean
   _warnHtmlInMessage: WarnHtmlInMessageLevel
   _postTranslation: ?PostTranslationHandler
@@ -101,6 +102,7 @@ export default class VueI18n {
     this._numberFormatters = {}
     this._path = new I18nPath()
     this._dataListeners = []
+    this._componentInstanceCreatedListener = options.componentInstanceCreatedListener || null
     this._preserveDirectiveContent = options.preserveDirectiveContent === undefined
       ? false
       : !!options.preserveDirectiveContent
@@ -227,6 +229,12 @@ export default class VueI18n {
     }, { immediate: true })
   }
 
+  onComponentInstanceCreated (newI18n: I18n) {
+    if (this._componentInstanceCreatedListener) {
+      this._componentInstanceCreatedListener(newI18n, this)
+    }
+  }
+
   get vm (): any { return this._vm }
 
   get messages (): LocaleMessages { return looseClone(this._getMessages()) }

src/mixin.js

@@ -29,16 +29,19 @@ export default {
         this._i18n = options.i18n
         this._i18nWatcher = this._i18n.watchI18nData()
       } else if (isPlainObject(options.i18n)) {
+        const rootI18n = this.$root && this.$root.$i18n && this.$root.$i18n instanceof VueI18n
+          ? this.$root.$i18n
+          : null
         // component local i18n
-        if (this.$root && this.$root.$i18n && this.$root.$i18n instanceof VueI18n) {
+        if (rootI18n) {
           options.i18n.root = this.$root
-          options.i18n.formatter = this.$root.$i18n.formatter
-          options.i18n.fallbackLocale = this.$root.$i18n.fallbackLocale
-          options.i18n.formatFallbackMessages = this.$root.$i18n.formatFallbackMessages
-          options.i18n.silentTranslationWarn = this.$root.$i18n.silentTranslationWarn
-          options.i18n.silentFallbackWarn = this.$root.$i18n.silentFallbackWarn
-          options.i18n.pluralizationRules = this.$root.$i18n.pluralizationRules
-          options.i18n.preserveDirectiveContent = this.$root.$i18n.preserveDirectiveContent
+          options.i18n.formatter = rootI18n.formatter
+          options.i18n.fallbackLocale = rootI18n.fallbackLocale
+          options.i18n.formatFallbackMessages = rootI18n.formatFallbackMessages
+          options.i18n.silentTranslationWarn = rootI18n.silentTranslationWarn
+          options.i18n.silentFallbackWarn = rootI18n.silentFallbackWarn
+          options.i18n.pluralizationRules = rootI18n.pluralizationRules
+          options.i18n.preserveDirectiveContent = rootI18n.preserveDirectiveContent
         }
 
         // init locale messages via custom blocks
@@ -67,6 +70,10 @@ export default {
         if (options.i18n.sync === undefined || !!options.i18n.sync) {
           this._localeWatcher = this.$i18n.watchLocale()
         }
+
+        if (rootI18n) {
+          rootI18n.onComponentInstanceCreated(this._i18n)
+        }
       } else {
         if (process.env.NODE_ENV !== 'production') {
           warn(`Cannot be interpreted 'i18n' option.`)

types/index.d.ts

@@ -87,6 +87,7 @@ declare namespace VueI18n {
 
   type MissingHandler = (locale: Locale, key: Path, vm: Vue | null, values: any) => string | void;
   type PostTranslationHandler = (str: string, key?: string) => string;
+  type ComponentInstanceCreatedListener = (newVm: VueI18n & IVueI18n, rootVm: VueI18n & IVueI18n) => void;
 
   interface IntlAvailability {
     dateTimeFormat: boolean;
@@ -113,6 +114,7 @@ declare namespace VueI18n {
     warnHtmlInMessage?: WarnHtmlInMessageLevel;
     sharedMessages?: LocaleMessages;
     postTranslation?: PostTranslationHandler;
+    componentInstanceCreatedListener?: ComponentInstanceCreatedListener;
   }
 }
 

vuepress/api/README.md

@@ -340,6 +340,18 @@ A handler for post processing of translation. The handler gets after being calle
 
 This handler is useful if you want to filter on translated text such as space trimming.
 
+#### componentInstanceCreatedListener
+
+> 8.18+
+
+  * **Type:** `ComponentInstanceCreatedListener`
+
+  * **Default:** `null`
+
+A handler for getting notified when component-local instance was created. The handler gets called with new and old (root) VueI18n instances.
+
+This handler is useful when extending the root VueI18n instance and wanting to also apply those extensions to component-local instance.
+
 ### Properties
 
 #### locale

vuepress/ru/api/README.md

@@ -344,6 +344,18 @@ sidebar: auto
 
 Может пригодиться при необходимости дополнительно обработать итоговый текст перевода, например избавиться от висящих пробелов.
 
+#### componentInstanceCreatedListener
+
+> 8.18+
+
+  * **Type:** `ComponentInstanceCreatedListener`
+
+  * **Default:** `null`
+
+A handler for getting notified when component-local instance was created. The handler gets called with new and old (root) VueI18n instances.
+
+This handler is useful when extending the root VueI18n instance and wanting to also apply those extensions to component-local instance.
+
 ### Свойства
 
 #### locale