Stronger locale detection

Fixes #38

Author: AFCMS

package.json

@@ -17,6 +17,7 @@
     },
     "dependencies": {
         "@lingui/core": "^5.5.1",
+        "@lingui/detect-locale": "^5.5.1",
         "@lingui/react": "^5.5.1",
         "@tailwindcss/vite": "^4.1.15",
         "@vercel/analytics": "^1.5.0",

pnpm-lock.yaml

@@ -1,11 +1,17 @@
+import { detect, fromStorage, fromNavigator } from "@lingui/detect-locale";
+
 import supportedLocales, { type SupportedLocale } from "./supported_locales";
 
+const DEFAULT_FALLBACK = "en";
+
 export function isSupportedLocale(locale: string): locale is SupportedLocale {
   return (supportedLocales as readonly string[]).includes(locale);
 }
 
 export function getLanguage(): SupportedLocale {
-  const lang = navigator.language;
+  const lang =
+    detect(fromStorage("lang"), fromNavigator(), DEFAULT_FALLBACK) ??
+    DEFAULT_FALLBACK;
   const sanitizedLang = lang.split("-")[0];
-  return isSupportedLocale(sanitizedLang) ? sanitizedLang : "en";
+  return isSupportedLocale(sanitizedLang) ? sanitizedLang : DEFAULT_FALLBACK;
 }