feat(i18n): improve i18n types

packages/core/i18n/src/i18n.ts

@@ -84,7 +84,7 @@ l10n.localeChangeSignal.addListener(
       logger.logMethodArgs('localeChange', locale);
       l10n.locale = locale;
 
-      if (l10n.resourceChangeSignal.value?._localCode !== locale.code) {
+      if (l10n.resourceChangeSignal.value?._code !== locale.code) {
         l10n.resourceChangeSignal.expire();
         if (l10n.config.autoFetchResources) {
           l10n.resourceChangeSignal.request(locale);
@@ -124,7 +124,15 @@ l10n.resourceChangeSignal.setProvider(async (locale) => {
     });
 
     if (response.ok) {
-      return response.json();
+      const resource = (await response.json()) as L10Resource;
+      if (resource._code == null) {
+        logger.accident('resourceProvider', 'resource_not_valid', 'Key `_code` not defined in l10n resource', {
+          url,
+          resource,
+        });
+        throw new Error('resource_not_valid');
+      }
+      return resource;
     }
     else {
       throw new Error('fetch_nok');
@@ -133,6 +141,7 @@ l10n.resourceChangeSignal.setProvider(async (locale) => {
   catch (err) {
     logger.error('resourceProvider', 'fetch_failed', (err as Error).stack || err, {locale, url});
     // TODO: user error signal.
+    return;
   }
 });
 
@@ -141,8 +150,11 @@ l10n.resourceChangeSignal.setProvider(async (locale) => {
  *
  * @param key The String_Key of the translation resource to localize.
  * @returns The localized string.
+ *
  *  return `…` if the translation resource is not yet loaded.
- *  return `(key)` if the key not defined in the translation resource.
+ *
+ *  return `{key}` if the key not defined in the translation resource.
+ *
  *  return null if the key is null or undefined (for optional input).
  *
  * @example
@@ -154,8 +166,11 @@ function localize(key?: null): null;
  *
  * @param key The String_Key of the translation resource to localize.
  * @returns The localized string.
+ *
  *  return `…` if the translation resource is not yet loaded.
- *  return `(key)` if the key not defined in the translation resource.
+ *
+ *  return `{key}` if the key not defined in the translation resource.
+ *
  *  return null if the key is null or undefined (for optional input).
  *
  * @example
@@ -167,8 +182,11 @@ function localize(key: string): string;
  *
  * @param key The String_Key of the translation resource to localize.
  * @returns The localized string.
+ *
  *  return `…` if the translation resource is not yet loaded.
- *  return `(key)` if the key not defined in the translation resource.
+ *
+ *  return `{key}` if the key not defined in the translation resource.
+ *
  *  return null if the key is null or undefined (for optional input).
  *
  * @example

packages/core/i18n/src/type.ts

@@ -9,21 +9,22 @@ declare global {
   }
 }
 
-export type L10Resource = {
-  [key: string]: string;
-  _localeCode: `${string}-${string}`;
+export type LocalCode = `${Lowercase<string>}-${Uppercase<string>}`;
+
+export type L10Resource = Record<string, string> & {
+  _code: LocalCode;
 };
 
 export type Locale = {
   /**
    * fa-IR, en-US, ...
    */
-  code: `${string}-${string}`;
+  code: LocalCode;
 
   /**
    * fa, en, ...
    */
-  language: string;
+  language: Lowercase<string>;
 
   /**
    * ltr, rtl