From 06400ad2b5d11963d3beeb1ecc392d44b0d5c6c7 Mon Sep 17 00:00:00 2001
From: Jan Amann <jan@amann.work>
Date: Sat, 21 Sep 2024 04:23:50 +0200
Subject: [PATCH] fix: Use default messages from `en` as fallback if messages
 are missing in another locale (#7054)

* fix: Use default messages from `en` as fallback if messages are missing in another locale

* chore: Remove `deepmerge` dependency in favor of a more optimized custom function

* chore: Revert changes to lockfile
---
 apps/site/i18n.tsx          | 19 +++++++++++++------
 apps/site/util/deepMerge.ts | 20 ++++++++++++++++++++
 2 files changed, 33 insertions(+), 6 deletions(-)
 create mode 100644 apps/site/util/deepMerge.ts

diff --git a/apps/site/i18n.tsx b/apps/site/i18n.tsx
index 5e235d8e3d15..efed3f4d9c6f 100644
--- a/apps/site/i18n.tsx
+++ b/apps/site/i18n.tsx
@@ -3,20 +3,27 @@ import { getRequestConfig } from 'next-intl/server';
 
 import { availableLocaleCodes } from '@/next.locales.mjs';
 
+import deepMerge from './util/deepMerge';
+
 // Loads the Application Locales/Translations Dynamically
 const loadLocaleDictionary = async (locale: string) => {
+  // This enables HMR on the English Locale, so that instant refresh
+  // happens while we add/change texts on the source locale
+  const defaultMessages = await import(
+    '@node-core/website-i18n/locales/en.json'
+  ).then(f => f.default);
+
   if (locale === 'en') {
-    // This enables HMR on the English Locale, so that instant refresh
-    // happens while we add/change texts on the source locale
-    return import('@node-core/website-i18n/locales/en.json').then(
-      f => f.default
-    );
+    return defaultMessages;
   }
 
   if (availableLocaleCodes.includes(locale)) {
     // Other languages don't really require HMR as they will never be development languages
     // so we can load them dynamically
-    return importLocale(locale);
+    const messages = await importLocale(locale);
+
+    // Use default messages as fallback
+    return deepMerge(defaultMessages, messages);
   }
 
   throw new Error(`Unsupported locale: ${locale}`);
diff --git a/apps/site/util/deepMerge.ts b/apps/site/util/deepMerge.ts
new file mode 100644
index 000000000000..751c09a3afe1
--- /dev/null
+++ b/apps/site/util/deepMerge.ts
@@ -0,0 +1,20 @@
+export default function deepMerge<Obj1 extends object, Obj2 extends object>(
+  obj1: Obj1,
+  obj2: Obj2
+): Obj1 & Obj2 {
+  const result = { ...obj1 } as Obj1 & Obj2;
+
+  for (const key in obj2) {
+    if (Object.prototype.hasOwnProperty.call(obj2, key)) {
+      if (typeof obj2[key] === 'object' && obj2[key] !== null) {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        result[key] = deepMerge(result[key] as any, obj2[key] as any);
+      } else {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        result[key] = obj2[key] as any;
+      }
+    }
+  }
+
+  return result;
+}