feat: translate funcs

src/core/localization/strings.ts

@@ -0,0 +1,17 @@
+const LANGUAGES = ['en-US', 'es-ES', 'ja-JP'] as const;
+
+export type Language = (typeof LANGUAGES)[number];
+export type TranslationFragmentTree = {
+  [key: string]: TranslationFragment;
+} & {
+  $?: string;
+};
+export type TranslationFragment = string | TranslationFragmentTree;
+
+export const translations = LANGUAGES.reduce(
+  (table, language) => ({
+    ...table,
+    [language]: import(`../../lang/${language}.json`),
+  }),
+  {},
+) as Record<Language, Promise<TranslationFragment>>;

src/core/localization/translator.ts

@@ -0,0 +1,42 @@
+import { Language, translations } from './strings';
+
+export async function translator(language: Language) {
+  const strings = await translations[language];
+
+  function translate(key: string) {
+    const path = key.split('.');
+    let fragment = strings;
+
+    for (const pathItem in path) {
+      if (typeof fragment === 'string') {
+        throw new SyntaxError(
+          `Attempted to access sub-string ("${pathItem}" in "${path}") from a string instead of a tree`,
+        );
+      } else {
+        fragment = fragment[pathItem];
+
+        if (typeof fragment === 'undefined') {
+          throw new Error(
+            `Undefined translation for key "${key}" (in "${path}") in language "${language}"`,
+          );
+        }
+      }
+    }
+
+    if (typeof fragment === 'string') {
+      return fragment;
+    } else if (fragment.$) {
+      return fragment.$!;
+    } else {
+      throw new Error(
+        `Unresolved tree ending for path "${path}" in language "${language}"`,
+      );
+    }
+  }
+
+  function t(strings: TemplateStringsArray) {
+    return translate(strings[0]);
+  }
+
+  return { translate, t };
+}