优化性能钩子useMemo

执行顺序

useMemo 是同步执行，而 useEffect 是异步的。

import { useMemo, useState, useEffect } from 'react';function TestComponent() {const [count, setCount] = useState(0);console.log('普通代码：在渲染期间同步执行');useMemo(() => {console.log('useMemo：在渲染期间同步执行');}, [count]);useEffect(() => {console.log('useEffect：在渲染后异步执行，不阻塞渲染）');}, [count]);return (<div><p>Count: {count}</p><button onClick={() => setCount(count + 1)}>Increment</button></div>);
}
export default TestComponent;