feat: use URL query to select language

Author: Neet-Nestor

app/components/home.tsx

@@ -18,7 +18,7 @@ import { ServiceWorkerMLCEngine } from "@mlc-ai/web-llm";
 import MlcIcon from "../icons/mlc.svg";
 import LoadingIcon from "../icons/three-dots.svg";
 
-import Locale from "../locales";
+import Locale, { changeLang, AllLangs, Lang } from "../locales";
 import { getCSSVar, useMobileScreen } from "../utils";
 import { DEFAULT_MODELS, Path, SlotID } from "../constant";
 import { ErrorBoundary } from "./error";

app/locales/index.ts

@@ -104,6 +104,16 @@ function getLanguage() {
 }
 
 export function getLang(): Lang {
+  if (typeof window !== "undefined") {
+    const params = new URLSearchParams(window.location.search);
+    if (
+      params.get("lang") &&
+      AllLangs.includes(params.get("lang")!.toLowerCase() as Lang)
+    ) {
+      return params.get("lang") as Lang;
+    }
+  }
+
   const savedLang = getItem(LANG_KEY);
 
   if (AllLangs.includes((savedLang ?? "") as Lang)) {