feat: componentInstanceCreatedListener option (#58)

* feat: componentInstanceCreatedListener option

* fix: lint errors

Author: kazupon

README.md

@@ -212,6 +212,7 @@ yarn add vue-i18n@next
     - [x] preserveDirectiveContent
     - [x] warnHtmlInMessage
     - [x] postTranslation
+    - [x] componentInstanceCreatedListener
     - [x] t
     - [x] tc
     - [x] te

src/legacy.ts

@@ -58,6 +58,10 @@ export interface Formatter {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   interpolate(message: string, values: any, path: string): Array<any> | null
 }
+export type ComponentInstanceCreatedListener = (
+  target: VueI18n,
+  global: VueI18n
+) => void
 
 /**
  *  VueI18n Options
@@ -85,6 +89,7 @@ export interface VueI18nOptions {
   pluralizationRules?: PluralizationRules
   postTranslation?: PostTranslationHandler
   sync?: boolean
+  componentInstanceCreatedListener?: ComponentInstanceCreatedListener
 }
 
 /**
@@ -156,6 +161,7 @@ export interface VueI18n {
 export interface VueI18nInternal {
   __id: number
   __composer: Composer
+  __onComponentInstanceCreated(target: VueI18n): void
 }
 
 /**
@@ -253,7 +259,7 @@ export function createVueI18n(
 
   // defines VueI18n
   const vueI18n = {
-    /*!
+    /**
      * properties
      */
 
@@ -516,6 +522,14 @@ export function createVueI18n(
       __DEV__ &&
         warn(getWarnMessage(I18nWarnCodes.NOT_SUPPORTED_GET_CHOICE_INDEX))
       return -1
+    },
+
+    // for internal
+    __onComponentInstanceCreated(target: VueI18n): void {
+      const { componentInstanceCreatedListener } = options
+      if (componentInstanceCreatedListener) {
+        componentInstanceCreatedListener(target, vueI18n)
+      }
     }
   }
 

src/mixin.ts

@@ -160,13 +160,15 @@ export function defineMixin(
         }
         optionsI18n.__root = composer
         this.$i18n = createVueI18n(optionsI18n)
+        legacy.__onComponentInstanceCreated(this.$i18n)
 
         i18n._setLegacy(instance, this.$i18n)
       } else if (options.__i18n) {
         this.$i18n = createVueI18n({
           __i18n: options.__i18n,
           __root: composer
         })
+        legacy.__onComponentInstanceCreated(this.$i18n)
 
         i18n._setLegacy(instance, this.$i18n)
       } else {

test/mixin.test.ts

@@ -176,6 +176,25 @@ test('$i18n', async () => {
   expect(vm.$i18n.t('hello')).toEqual('hello!')
 })
 
+test('VueI18n componentInstanceCreatedListener option', async () => {
+  const componentInstanceCreatedListener = jest.fn()
+  const i18n = createI18n({
+    legacy: true,
+    locale: 'en',
+    componentInstanceCreatedListener
+  })
+
+  const App = defineComponent({
+    template: '<br/>',
+    i18n: {
+      locale: 'ja'
+    }
+  })
+  await mount(App, i18n)
+
+  expect(componentInstanceCreatedListener).toHaveBeenCalled()
+})
+
 test.skip('beforeDestroy', async () => {
   const i18n = createI18n({
     legacy: true,