Vue I18n Bridge for Legacy Projects

import Vue from 'vue';
import VueCompositionAPI from '@vue/composition-api';
import { createI18n, useI18n } from 'vue-i18n-bridge'; // Import from vue-i18n-bridge
import App from './App.vue';

// 1. Install Composition API for Vue 2
Vue.use(VueCompositionAPI);

// 2. Install vue-i18n (v8.x) with the bridge option
// Note: `vue-i18n-bridge` must also be installed via npm/yarn/pnpm
// For Vue 2.6, VueI18n constructor from 'vue-i18n' (v8) is passed as a second argument
// For Vue 2.7, this step might be slightly different with `vue-demi`
import VueI18n from 'vue-i18n'; // Legacy vue-i18n v8
Vue.use(VueI18n as any, { bridge: true }); // Important: tell v8.x to enable bridge mode

const messages = {
  en: {
    hello: 'Hello Vue 2 with i18n v9 features!',
    greeting: 'Welcome, {name}!'
  },
  es: {
    hello: '¡Hola Vue 2 con características de i18n v9!',
    greeting: '¡Bienvenido, {name}!'
  }
};

// 3. Create the i18n instance using createI18n from vue-i18n-bridge
const i18n = createI18n({
  legacy: false, // Essential for using Composition API mode and vue-i18n@9 features
  locale: 'en',
  fallbackLocale: 'en',
  messages,
}, VueI18n); // Pass the VueI18n v8 constructor as the second argument for Vue 2.6

// Inject i18n instance into Vue 2 app
new Vue({
  i18n: i18n as any, // Type assertion often needed due to bridge's compatibility layer
  render: h => h(App),
}).$mount('#app');

// App.vue (example component using Composition API)
// Ensure you have a template like <template>...</template> in App.vue

/*
<script lang="ts">
import { defineComponent, ref } from '@vue/composition-api';
import { useI18n } from 'vue-i18n-bridge'; // Use useI18n from the bridge

export default defineComponent({
  name: 'App',
  setup() {
    const { t, locale } = useI18n(); // Access translation functions
    const username = ref('Developer');

    const switchLocale = (newLocale: string) => {
      locale.value = newLocale;
    };

    return {
      t,
      locale,
      username,
      switchLocale,
    };
  },
  template: `
    <div>
      <h1>{{ t('hello') }}</h1>
      <p>{{ t('greeting', { name: username }) }}</p>
      <p>Current Locale: {{ locale }}</p>
      <button @click="switchLocale('en')">English</button>
      <button @click="switchLocale('es')">Español</button>
    </div>
  `
});
</script>
*/