<div id="root">
</div>
const App = () => {
let ref = React.useRef(0);
React.useEffect(() => {
ref += 1;
console.log(ref); // 會變成 [object Object]1
}, []);
return (
<div>
</div>
);
}
const root = ReactDOM.createRoot(document.querySelector('#root'));
root.render(<App />);
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