Improve typed i18n infrastructure + explicit namespace

src/utils/i18n-typed.ts

@@ -0,0 +1,38 @@
+// @ts-ignore
+import i18n from "$/locales";
+
+export function getModuleForNamespace(namespace: string) {
+    return {
+        t: function <Str extends string>(...args: I18nTArgs<Str>): string {
+            const [s, options] = args;
+            return i18n.t(s, { ...options, ns: namespace });
+        },
+        changeLanguage: i18n.changeLanguage.bind(i18n),
+        setDefaultNamespace: i18n.setDefaultNamespace.bind(i18n),
+    };
+}
+
+type I18nTArgs<Str extends string> = Interpolations<Str> extends Record<string, never>
+    ? [Str] | [Str, Partial<Options>]
+    : [Str, Interpolations<Str> & Partial<Options>];
+
+interface Options {
+    ns: string; // namespace
+    nsSeparator: string | boolean; // By default, ":", which breaks strings containing that char
+    lng: string; // language
+}
+
+type Interpolations<Str extends string> = Record<ExtractVars<Str>, string | number>;
+
+type ExtractVars<Str extends string> = Str extends `${string}{{${infer Var}}}${infer StrRest}`
+    ? Var | ExtractVars<StrRest>
+    : never;
+
+/* Tests */
+
+type IsEqual<T1, T2> = [T1] extends [T2] ? ([T2] extends [T1] ? true : false) : false;
+const assertEqualTypes = <T1, T2>(_eq: IsEqual<T1, T2>): void => {};
+
+assertEqualTypes<ExtractVars<"">, never>(true);
+assertEqualTypes<ExtractVars<"name={{name}}">, "name">(true);
+assertEqualTypes<ExtractVars<"name={{name}} age={{age}}">, "name" | "age">(true);

src/utils/i18n.ts

@@ -1,35 +1,3 @@
-// @ts-ignore
-import i18n from "$/locales";
+import { getModuleForNamespace } from "./i18n-typed";
 
-function t<Str extends string>(s: Str, namespace?: GetNamespace<Str>): string {
-    return i18n.t(s, namespace);
-}
-
-interface Options {
-    nsSeparator: string | boolean;
-    lng: string;
-}
-
-type GetNamespace<Str extends string> = Record<ExtractVars<Str>, string | number> &
-    Partial<Options>;
-
-type ExtractVars<Str extends string> = Str extends `${string}{{${infer Var}}}${infer StrRest}`
-    ? Var | ExtractVars<StrRest>
-    : never;
-
-/* Tests */
-
-type IsEqual<T1, T2> = [T1] extends [T2] ? ([T2] extends [T1] ? true : false) : false;
-const assertEqualTypes = <T1, T2>(_eq: IsEqual<T1, T2>): void => {};
-
-assertEqualTypes<ExtractVars<"">, never>(true);
-assertEqualTypes<ExtractVars<"name={{name}}">, "name">(true);
-assertEqualTypes<ExtractVars<"name={{name}} age={{age}}">, "name" | "age">(true);
-
-const i18nTyped = {
-    t,
-    changeLanguage: i18n.changeLanguage.bind(i18n),
-    setDefaultNamespace: i18n.setDefaultNamespace.bind(i18n),
-};
-
-export default i18nTyped;
+export default getModuleForNamespace("dhis2-skeleton-app");