📅  最后修改于: 2022-03-11 15:03:11.993000             🧑  作者: Mango
const { useState, useEffect, useMemo } = React;
function App() {
const [count, setCount] = useState(50);
useEffect(() => {
setTimeout(() => {
setCount(150);
}, 2000);
}, []);
return ;
}
function DisplayCount(props) {
const count = useMemo(() => props.count > 100 ? 100 : props.count, [props.count]);
return {count} ;
}
ReactDOM.render( , document.getElementById("root"));