1.Test/xiangminmin/react/syudy4/src/components/7_Hooks_useMemo.jsx

import { useMemo,useState } from "react";

export default function Memo({name}){

    let [Num,setNum] = useState(7)

    // useMemo类似于Vue中的计算属性,缓存功效，缓存值
    // useMemo(()=>{}，[依赖项])
    // 一定要判断场景 使用useMemo
    // let newNum = useMemo(()=>Num+10,[Num])
    let newNum = useMemo(()=>{
        console.log('useMemo执行了');
        return Num+10
    },[Num])

    return (
        <div>
            <h3>{newNum}</h3>
            <p>{name}</p>
        </div>
    )
}