/vue-i18n-skilld

Legacy API mode (deprecated)

Legacy API mode reproduces the vue-i18n v8 API on Vue 3 for migration. Deprecated in v11, removed in v12. Do not start new work here; migrate with https://vue-i18n.intlify.dev/guide/migration/vue3.html.

What activates it

createI18n({ legacy: true }) (the default). The I18n.global property then returns a VueI18n instance instead of a Composer (dist/vue-i18n.d.ts:1699), and I18n.mode reports 'legacy' (deprecated, dist/vue-i18n.d.ts:1686-1690).

Surface still present in 11.4.12

The VueI18n interface (dist/vue-i18n.d.ts:2154-2486) mirrors the v8 class: locale, fallbackLocale, t, d, n, te, tm, rt, getLocaleMessage, setLocaleMessage, mergeLocaleMessage, plus pluralizationRules (Legacy name; Composition uses pluralRules).

Component globals: $t, $d, $n, $rt, $te, $tm, $tc (removed), $i18n (the VueI18nInstance union, dist/vue-i18n.d.ts:2557).

Migration moves

1. Set legacy: false in createI18n.
2. Keep $t in templates working with globalInjection: true (default) while you convert scripts.
3. Replace Options API this.$t / this.$i18n with useI18n() in setup.
4. Replace pluralizationRules with pluralRules.
5. Drop any allowComposition usage (removed in v10).
6. Remove v-t directives (also deprecated independently).

Options API note

Options API components (this.$t) imply Legacy mode wiring. Options API without legacy injections: use useI18n() inside a setup() block; the Composition API works in both script styles.

Docs: https://vue-i18n.intlify.dev/guide/advanced/composition.html#legacy-api-mode, API: https://vue-i18n.intlify.dev/api/legacy.html