Breaking Changes in v11
NOTICE
Vue I18n v11 is still beta
Deprecate Legacy API mode
Reason
The Legacy API mode was the API mode compatible with v8 for Vue 2. When v9 was released, the Legacy API was provided to smooth the migration from v8 to v9.
Legacy API mode will be deprecated in v11, as previous vue-i18n releases have already provided the following to support migration to Composition API mode
- Migration from Legacy API mode to Composition API mode: https://vue-i18n.intlify.dev/guide/migration/vue3.html
- Composition API usage: https://vue-i18n.intlify.dev/guide/advanced/composition.html
For compatibility, Legacy API mode still works in v11, but will be removed entirely in v12, so Legacy API mode will not work after that version.
Deprecate Custom Directive v-t
Reason
The advantage of v-t was that it could optimize performance using the vue compiler transform and the pre-translation of vue-i18n-extension.
This feature was supported from Vue 2. About details see the blog article: https://medium.com/@kazu_pon/performance-optimization-of-vue-i18n-83099eb45c2d
In Vue 3, due to the Composition API, the pre-translation of vue-i18n-extension is now limited only for global scope.
In addition, Vue 3 Virtual DOM optimization has been introduced, and the optimization provided by vue-i18n-extension is no longer very effective. We need to require settings for SSR, the benefits of using v-t have disappeared. And DX of templates using v-t is not good. Custom directives do not work with key completion in editors (e.g. vscode).
For compatibility, v-t mode still works in v11, but will be removed entirely in v12, so v-t will not work after that version.
Drop tc and $tc for Legacy API mode
Reason: These APIs had already deprecated in warning about being dropped in v11. docs says, https://vue-i18n.intlify.dev/guide/migration/breaking10.html#deprecate-tc-and-tc-for-legacy-api-mode