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react/B/6/P03.html
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2022-01-10 00:07:02 +08:00
<!--
* @Author: chenxuan
* @Date: 2022-01-09 23:07:06
* @LastEditTime: 2022-01-10 00:02:29
* @LastEditors: chenxuan
-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>生命周期函数</title>
</head>
<body>
<div id="app"></div>
<script src="../package/old/react.development.js"></script>
<script src="../package/old/react-dom.development.js"></script>
<script src="../package/old/babel.min.js"></script>
<script type="text/babel">
class Count extends React.Component{
constructor(props){
console.log("1-constructor")
super(props)
this.state={count:100}
}
add=()=>{
let {count}=this.state;
count+=1;
this.setState({count})
}
death=()=>{
ReactDOM.unmountComponentAtNode(document.getElementById('app'))
}
// 强制更新不受shouldComponentUpdate控制
force=()=>{
this.forceUpdate()
}
render(){
console.log("3-render")
return (
<div>
<h2>当前求和为:{this.state.count}</h2>
<button onClick={this.add}>点我+1</button>
<button onClick={this.death}>销毁</button>
<button onClick={this.force}>强制更新</button>
</div>
)
}
componentWillMount(){
console.log("2-componentsWillMount")
}
componentDidMount(){
console.log('4-componentDidMount')
}
componentWillUnmount(){
console.log("5-componentWillUnmount")
}
// 控制组件更新的阀门
shouldComponentUpdate(){
console.log('shouldComponentUpdate')
return true
}
componentWillUpdate(){
console.log('componentWillUpdate')
}
componentDidUpdate(){
console.log('componentDidUpdate')
}
}
class A extends React.Component{
state={carName:"奔驰"}
changeCar=()=>{
this.setState({carName:"哈弗"})
}
render(){
return (
<div>
A
<B carName={this.state.carName} />
<button onClick={this.changeCar}>换车</button>
</div>
)
}
}
class B extends React.Component{
componentWillReceiveProps(props){
console.log("componentWillReceiveProps")
console.log("------")
console.log(props)
}
render(){
return (
<div>
<li>B</li>
<li>接收到的值:{this.props.carName}</li>
</div>
)
}
}
ReactDOM.render(
// <Count/>,document.getElementById('app')
<A/>,document.getElementById('app')
)
</script>
</body>
</html>