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父组件在挂载过程中，子组件又更新父组件

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司徒正美 edited this page Nov 7, 2017 · 1 revision 
<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <script type='text/javascript' src="./dist/React.js"></script>
    <!-- <script src="./test/react.js"></script>
    <script src="./test/react-dom.js"></script> -->
    <script src="./lib/babel.js"></script>
  
</head>

<body>

    <div>这个默认会被清掉</div>
    <div id='example'></div>
    <pre>
      
    </pre>

    <script type='text/babel'>
    var container = document.getElementById("example")
    var div = container
   var expect = function(a) {
      return {
          toBe: function(b) {
              console.log(a,"\nvs\n", b, a === b)
          }
      }
  }
 

var list = [];
var flag = 1
 function logger(e){
   console.log(e)
 }
 var parentIntance 
 class Page extends React.Component{
     constructor(props){
        super(props)
        this.state = {
            a: 111,
            b: 222,
            c: 333
        }
        parentIntance = this
     }
     render(){
         console.log("Page.render()")
         return <div>
            <A  name="a" text={this.state.a} />
            <A  name="b" text={this.state.b} />
            <A  name="c" text={this.state.c} />
            </div>
     }
 }
 class A extends React.Component {
     constructor(props) {
         super(props);
         this.state = {
             text: props.text
         };
     }

     componentDidMount() {
         logger(this.props.name + " did mount");
         if(this.props.name === "a"){
             console.log("父组件更新")
            parentIntance.setState({
                a: 444
            })
         }
      //   ReactDOM.render(<div>{this.state.text}</div>, div);
     
     }
     componentWillReceiveProps(nextProps){
        logger(this.props.name + " will receive "+nextProps.text +" "+ this.props.text);
        if(nextProps.text !== this.props.text){
            this.setState({
                text: nextProps.text
            })
        }

     }
     componentDidUpdate() {
        logger(this.props.name + " did update");
     }
     render() {
         return <div className={this.props.name}>{this.state.text}</div>;
     }
 }
 
 var s = ReactDOM.render(<Page />, div);

``html

<script type='text/javascript' src="./dist/React.js"></script> <script type='text/javascript' src="./test/react.development.js"></script> <script type='text/javascript' src="./test/react-dom.development.js"></script> 
<script type='text/javascript' src="./lib/babel.js"></script>

    <pre>应该等于
       
      
    </pre>
    <h1 id='root' class="root">

    </h1>
    <script type='text/babel'>
       var container = document.getElementById("example")
        var div = container
        var PropTypes = React.PropTypes
        if(!window.ReactDOM){
          window.ReactDOM = React
        }
        var expect = function(a) {
            return {
                toBe: function(b) {
                    console.log(a,"vs", b, a === b)
                },
                toEqual(b){
                    console.log(a,"vs", b, a +""=== b+"")
                },
                toThrow(b){
                    try{
                        a()
                    }catch(e){
                        console.log(e,"vs", b, e.message +""=== b+"")
                    }
                }
            }
        }

        const Hello = ({ name }) => <h1>Hello {name}!</h1>;
        
        class ShowMyError extends React.Component {
          constructor(props) {
            super(props);
            this.state = { error: false };
          }
        
          componentDidCatch(error, info) {
              console.log(error, info)
            this.setState({ error, info });
          }
        
          render() {
            if (this.state.error) {
              return (
                <div>
                  <h1>
                    Error AGAIN: {this.state.error.toString()}
                  </h1>
                  {this.state.info &&
                    this.state.info.componentStack.split("\n").map(i => {
                      return (
                        <div key={i}>
                          {i}
                        </div>
                      );
                    })}
                </div>
              );
            }
            return this.props.children;
          }
        }
        
        class Broken extends React.Component {
          constructor(props) {
            super(props);
            this.state = { throw: false, count: 0 };
          }
        
          render() {
            if (this.state.throw) {
              throw new Error("YOLO");
            }
        
            return (
              <div>
                <button
                  onClick={e => {
                    this.setState({ throw: true });
                  }}
                >
                  button will render error.
                </button>
        
                <button onClick={e => {
                  this.setState(({ count }) => ({
                    count: count + 1
                  }));
                }}>button will not throw</button>
        
                <div>
                  {"All good here. Count: "}{this.state.count}
                </div>
              </div>
            );
          }
        }
        
        class App extends React.Component {
          render() {
            const styles = {
              fontFamily: "sans-serif",
              textAlign: "center"
            };
            return (
              <div style={styles}>
                <Hello name="ShowMyError" />
                <h2>
                  Start clicking to see some {"\u2728"}magic{"\u2728"}
                </h2>
                <ShowMyError>
                  <Broken />
                </ShowMyError>
              </div>
            );
          }
        }
        
        ReactDOM.render(<App />, document.getElementById("root"));
</script> ```
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