关于react.js:react中PureComponent的实现

Component和PureComponent最大的不同是PureComponent通过shouldComponentUpdate()来比拟prop和state的新旧值，从而决定是是否更新组件，当然这里的比拟是浅比拟（shallowEqual），这里贴一段实现PureComponent的代码：

import React, { Component } from 'react'export default class PureComponent extends Component {  shouldComponentUpdate(nextProps, nextState) {    return (      !shallowEqual(this.props, nextProps) ||      !shallowEqual(this.state, nextState)    )  }}function shallowEqual(obj1, obj2) {  if (obj1 === obj2) return true  if (    obj1 === null ||    obj2 === null ||    typeof obj1 !== 'object' ||    typeof obj2 !== 'object'  ) {    return false  }  let keys1 = Object.keys(obj1)  let keys2 = Object.keys(obj2)  if (keys1.length !== keys2.length) return false  for (let name of keys1) {    if (!obj2.hasOwnProperty(name) || obj1[name] != obj2[name]) {      return false    }  }  return true}

函数组件也能够用React.memo实现PureComponent的成果：

function memo(FunComp){  return class extends React.PureComponent{    render(){      return <FunComp {...this.props} />    }  }}