feat: strict typing for i18n function and component

ts/types/Localizer.ts

@@ -0,0 +1,31 @@
+import type { Dictionary } from '../localization/locales';
+
+/** A localization dictionary key */
+type Token = keyof Dictionary;
+
+/** A dynamic argument that can be used in a localized string */
+type DynamicArg = string | number;
+
+/** A record of dynamic arguments for a specific key in the localization dictionary */
+type ArgsRecord<T extends Token> = Record<DynamicArgs<Dictionary[T]>, DynamicArg>;
+
+/** The dynamic arguments in a localized string */
+type DynamicArgs<LocalizedString extends string> =
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  LocalizedString extends `${infer _Pre}{${infer Var}}${infer Rest}`
+    ? Var | DynamicArgs<Rest>
+    : never;
+
+/** The arguments for retrieving a localized message */
+export type GetMessageArgs<T extends Token> =
+  DynamicArgs<Dictionary[T]> extends never ? [T] : [T, ArgsRecord<T>];
+
+/** The props for the localization component */
+export type I18nProps<T extends Token> =
+  DynamicArgs<Dictionary[T]> extends never ? { token: T } : { token: T; args: ArgsRecord<T> };
+
+/** The dictionary of localized strings */
+export type LocalizerDictionary = Dictionary;
+
+/** A localization dictionary key */
+export type LocalizerToken = keyof LocalizerDictionary;