feat(i18n): Custom translation function can now be static

.changeset/ninety-spiders-return.md

@@ -0,0 +1,5 @@
+---
+"sit-onyx": minor
+---
+
+Custom translation function can now be static

packages/sit-onyx/src/i18n/index.ts

@@ -1,12 +1,4 @@
-import {
-  computed,
-  inject,
-  unref,
-  type App,
-  type ComputedRef,
-  type InjectionKey,
-  type MaybeRef,
-} from "vue";
+import { computed, inject, readonly, toRef, type App, type InjectionKey, type MaybeRef } from "vue";
 import type { FlattenedKeysOf, TranslationValue } from "../types/i18n";
 import type { DeepPartial } from "../types/utils";
 import enUS from "./locales/en-US.json";
@@ -68,7 +60,7 @@ export type ProvideI18nOptions = {
    *
    * Note: If a custom `t` function is used, passed messages will not be used.
    */
-  t?: ComputedRef<TranslationFunction>;
+  t?: MaybeRef<TranslationFunction>;
 };
 
 export type TranslationFunction = (
@@ -87,11 +79,13 @@ const createI18n = (options: ProvideI18nOptions = {}) => {
    * Current locale.
    * @default "en-US"
    */
-  const locale = computed(() => unref(options?.locale) ?? "en-US");
+  const locale = readonly(toRef(options?.locale ?? "en-US"));
+  const userT = options.t ? readonly(toRef(options.t)) : undefined;
 
-  // If the user provided a custom `t` function it should be used instead of the default one
-  if (options.t) {
-    return { t: options.t, locale };
+  // If the user provided a custom `t` function, it is used instead of the default.
+  // Then we also skip the loading and applying of messages.
+  if (userT) {
+    return { t: userT, locale };
   }
 
   const messages = computed(() => {