ex4_state.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>Hello React</title>
    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
</head>
<body>
    <div id="root"></div>
    <!-- compilation JSX => JS -->
    <script type="text/babel">

    class App extends React.Component{
        
        constructor(props) {
            super(props);
            this.state = {
                unmount : false
            }
            this.cmpt = 0
        }

        render(){
            return (!this.state.unmount && <Clock/>);
        }

        componentDidMount(){
            setTimeout(() => {
                this.setState({
                    unmount: true
                })
            },5000)
        }
    }
    
    class Clock extends React.Component{
        constructor(props){
            super(props);
            this.state = {
                time: new Date().toLocaleTimeString()
            }
            this.timer = null
        }

        componentDidMount(){
            console.log('Component is mounted');
            this.timer = setInterval(() => {
                this.setState({
                    time: new Date().toLocaleTimeString()
                })
            }, 1000);
        }

        componentDidUpdate(){
            console.log('Render is updated');
        }

        componentWillUnmount(){
            console.log('Component is unmounted');
            clearInterval(this.timer)
        }
        
        render() {
            return (
                <div className="horloge">
                    {this.state.time}
                </div>
            )
        }
    }

    // TODO
    
    const container = document.getElementById('root');
    

    ReactDOM.render(
        <App />,
        container
    );


    </script>
</body>
</html>