no message

chenxuan1/src/pages/life.jsx

@@ -1,18 +1,43 @@
 import React from 'react';
-class Life extends React.Component {
+import ReactDOM from 'react-dom';
+class Child extends React.Component{
+  state={count:0}
+ 
   componentDidMount() {
     console.log('componentDidMount');
   }
   componentDidUpdate() {
     console.log('componentDidUpdate');
   }
-  componentWillUnmount() {
-    console.log('componentWillUnmount');
+  // 劫持state
+  // state属性与props相关时
+  static getDerivedStateFromProps(props,state){
+    console.log("getDerivedStateFromProps")
+    // return {count:"xxx"}
+    return null;
+}
+  add=()=>{
+      let {count}=this.state;
+      count+=1;
+      this.setState({count})
   }
+  render(){
+    return (
+      <div>
+        <h1>子组件</h1>
+        <h3>state:{this.state.count}</h3>
+        <h3>props:{this.props.name}</h3>
+        <button onClick={this.add}>子组件点击事件</button>
+      </div>
+    )
+  }
+}
+class Life extends React.Component {
+
   render() {
     return (
       <div>
-        <h1>生命周期函数</h1>
+        <Child name="chenxuan" />
       </div>
     );
   }