import * as React from "react"; import { useAtom, atom } from "jotai"; const refAtom = atom<HTMLDivElement>(null); const App: React.FC = () => { // 型定義はatomを継承 const [element, setElement] = useAtom(refAtom); React.useEffect(() => { if (element) return console.log(element); }, [element]); return ( <div ref={setElement}>Hrllo, World!</div> ) }