Refactor i18n client and server initialization

The refactor includes the removal of clientInstance checks as they are unnecessary. Also, i18n-provider.tsx has been updated to use react-query instead of local state for client initialization. Lastly, error handling has been added to the server initialization process and the @tanstack/react-query package has been added to the project dependencies.

packages/i18n/package.json

@@ -20,6 +20,7 @@
     "@kit/shared": "workspace:^",
     "@kit/tailwind-config": "workspace:*",
     "@kit/tsconfig": "workspace:*",
+    "@tanstack/react-query": "5.29.2",
     "i18next": "^23.11.2",
     "i18next-browser-languagedetector": "7.2.1",
     "i18next-resources-to-backend": "^1.2.1",

packages/i18n/src/i18n-provider.tsx

@@ -1,8 +1,7 @@
 'use client';
 
-import type { InitOptions, i18n } from 'i18next';
-
-let client: i18n;
+import { useSuspenseQuery } from '@tanstack/react-query';
+import type { InitOptions } from 'i18next';
 
 type Resolver = (
   lang: string,
@@ -17,23 +16,32 @@ export function I18nProvider({
   settings: InitOptions;
   resolver: Resolver;
 }>) {
-  // If the client is not initialized or
-  // the language has changed, reinitialize the client
-  if (!client || client.language !== settings.lng) {
-    throw withI18nClient(settings, resolver);
-  }
+  useI18nClient(settings, resolver);
 
   return children;
 }
 
-async function withI18nClient(settings: InitOptions, resolver: Resolver) {
-  if (typeof window !== 'undefined') {
-    const { initializeI18nClient } = await import('./i18n.client');
+/**
+ * @name useI18nClient
+ * @description A hook that initializes the i18n client.
+ * @param settings
+ * @param resolver
+ */
+function useI18nClient(settings: InitOptions, resolver: Resolver) {
+  return useSuspenseQuery({
+    queryKey: ['i18n', settings.lng],
+    queryFn: async () => {
+      const isBrowser = typeof window !== 'undefined';
 
-    client = await initializeI18nClient(settings, resolver);
-  } else {
-    const { initializeServerI18n } = await import('./i18n.server');
+      if (isBrowser) {
+        const { initializeI18nClient } = await import('./i18n.client');
 
-    client = await initializeServerI18n(settings, resolver);
-  }
+        return await initializeI18nClient(settings, resolver);
+      } else {
+        const { initializeServerI18n } = await import('./i18n.server');
+
+        return await initializeServerI18n(settings, resolver);
+      }
+    },
+  });
 }

packages/i18n/src/i18n.client.ts

@@ -3,8 +3,6 @@ import LanguageDetector from 'i18next-browser-languagedetector';
 import resourcesToBackend from 'i18next-resources-to-backend';
 import { initReactI18next } from 'react-i18next';
 
-let clientInstance: i18n | null = null;
-
 /**
  * Initialize the i18n instance on the client.
  * @param settings - the i18n settings
@@ -14,10 +12,6 @@ export async function initializeI18nClient(
   settings: InitOptions,
   resolver: (lang: string, namespace: string) => Promise<object>,
 ): Promise<i18n> {
-  if (clientInstance) {
-    return Promise.resolve(clientInstance);
-  }
-
   await i18next
     .use(
       resourcesToBackend(async (language, namespace, callback) => {
@@ -47,7 +41,5 @@ export async function initializeI18nClient(
       },
     );
 
-  clientInstance = i18next;
-
-  return clientInstance;
+  return i18next;
 }

packages/i18n/src/i18n.server.ts

@@ -14,10 +14,6 @@ export async function initializeServerI18n(
 ) {
   const i18nInstance = createInstance();
 
-  if (i18nInstance.isInitialized) {
-    return i18nInstance;
-  }
-
   await i18nInstance
     .use(
       resourcesToBackend(async (language, namespace, callback) => {
@@ -36,11 +32,20 @@ export async function initializeServerI18n(
       }),
     )
     .use(initReactI18next)
-    .init(settings);
+    .init(settings, (error) => {
+      if (error) {
+        console.error('Error initializing i18n server', error);
+      }
+    });
 
   return i18nInstance;
 }
 
+/**
+ * Parse the accept-language header value and return the languages that are included in the accepted languages.
+ * @param languageHeaderValue
+ * @param acceptedLanguages
+ */
 export function parseAcceptLanguageHeader(
   languageHeaderValue: string | null | undefined,
   acceptedLanguages: string[],