1function App() {
2 const [seconds, setSeconds] = React.useState(10);
3
4 React.useEffect(() => {
5 if (seconds > 0) {
6 setTimeout(() => setSeconds(seconds - 1), 1000);
7 } else {
8 setSeconds('BOOOOM!');
9 }
10 });
11
12 return (
13 <div className="App">
14 <div>
15 {seconds}
16 </div>
17 </div>
18 );
19}
20