我正在尝试新的React Hooks并且有一个带有计数器的Clock组件,它应该每秒都会增加.但是,该值不会超过一个.
function Clock() {
const [time, setTime] = React.useState(0);
React.useEffect(() => {
const timer = window.setInterval(() => {
setTime(time + 1);
}, 1000);
return () => {
window.clearInterval(timer);
};
}, []);
return (
<div>Seconds: {time}</div>
);
}
ReactDOM.render(<Clock />, document.querySelector('#app'));<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>