implement fallback language

apps/login/package.json

@@ -42,6 +42,7 @@
     "@zitadel/proto": "workspace:*",
     "clsx": "1.2.1",
     "copy-to-clipboard": "^3.3.3",
+    "deepmerge": "^4.3.1",
     "moment": "^2.29.4",
     "next": "14.2.14",
     "next-intl": "^3.20.0",

apps/login/src/app/(login)/layout.tsx

@@ -54,7 +54,7 @@ export default async function RootLayout({
                 <GlobalNav />
               ) : (
                 <div className="absolute bottom-0 right-0 flex flex-row p-4 items-center space-x-4">
-                  <LanguageSwitcher locale={`${locale}`} />
+                  {locale && <LanguageSwitcher locale={locale} />}
                   <Theme />
                 </div>
               )}

apps/login/src/i18n/request.ts

@@ -1,14 +1,20 @@
+import deepmerge from "deepmerge";
 import { getRequestConfig } from "next-intl/server";
 import { cookies } from "next/headers";
 
 export default getRequestConfig(async () => {
+  const fallback = "en";
   const cookiesList = cookies();
   const locale: string = cookiesList.get("NEXT_LOCALE")?.value ?? "en";
 
+  const userMessages = (await import(`../../locales/${locale}.json`)).default;
+  const fallbackMessages = (await import(`../../locales/${fallback}.json`))
+    .default;
+
   console.log("i18nRequest", locale);
 
   return {
     locale,
-    messages: (await import(`../../locales/${locale}.json`)).default,
+    messages: deepmerge(fallbackMessages, userMessages),
   };
 });

pnpm-lock.yaml

@@ -77,6 +77,9 @@ importers:
       copy-to-clipboard:
         specifier: ^3.3.3
         version: 3.3.3
+      deepmerge:
+        specifier: ^4.3.1
+        version: 4.3.1
       moment:
         specifier: ^2.29.4
         version: 2.30.1
@@ -1934,6 +1937,10 @@ packages:
   deep-is@0.1.4:
     resolution: {integrity: sha512-oIPzksmTg4/MriiaYGO+okXDT7ztn/w3Eptv/+gSIdMdKsJo0u4CfYNFJPy+4SKMuCqGw2wxnA+URMg3t8a/bQ==}
 
+  deepmerge@4.3.1:
+    resolution: {integrity: sha512-3sUqbMEc77XqpdNO7FRyRog+eW3ph+GYCbj+rK+uYyRMuwsVy0rMiVtPn+QJlKFvWP/1PYpapqYn0Me2knFn+A==}
+    engines: {node: '>=0.10.0'}
+
   define-data-property@1.1.4:
     resolution: {integrity: sha512-rBMvIzlpA8v6E+SJZoo++HAYqsLrkg7MSfIinMPFhmkorw7X+dOXVJQs+QT69zGkzMyfDnIMN2Wid1+NbL3T+A==}
     engines: {node: '>= 0.4'}
@@ -6317,6 +6324,8 @@ snapshots:
 
   deep-is@0.1.4: {}
 
+  deepmerge@4.3.1: {}
+
   define-data-property@1.1.4:
     dependencies:
       es-define-property: 1.0.0