excalidraw/excalidraw-app/app-language/language-state.ts

import { atom, useAtom } from "jotai";
import { useEffect } from "react";
import { getPreferredLanguage, languageDetector } from "./language-detector";

export const appLangCodeAtom = atom(getPreferredLanguage());

export const useAppLangCode = () => {
  const [langCode, setLangCode] = useAtom(appLangCodeAtom);

  useEffect(() => {
    languageDetector.cacheUserLanguage(langCode);
  }, [langCode]);

  return [langCode, setLangCode] as const;
};