lovecoding
/
VIP32


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./babel.min.js"></script>
    <script src="./react.development.js"></script>
    <script src="./react-dom.development.js"></script>
</head>
<body>
    <div id="root"></div>
    <script type="text/babel">
        const root = ReactDOM.createRoot(document.getElementById("root"));
        // 判断：
        // if - else - else-if 
        // switch case
        // 三元运算符：表达式 ? '真'：'假'
        function App() {
            return(
                <div>
                    <ToHome />    
                </div>
            )
        }
        // 登录
        // 逻辑：用户 => 首页 ； 非用户 => 登录页
        // function ToHome(username) {
        //     console.log(username,'哈哈哈哈')
        //     return username.user ? <h1>欢迎光临</h1> : <h1>go out</h1>
        // }
        // 登录
        // 逻辑：用户 => 首页 ； 非用户 => 登录页
        // 手动设置是不是用户通过本地存储
        function ToHome() {
            let token = JSON.parse(localStorage.getItem("token"));
            function handleLogin() {
                localStorage.setItem("token", JSON.stringify({
                    use:"喜羊羊",
                    age: 7
                }))
              token = JSON.parse(localStorage.getItem("token"))     
              console.log(token,'最新的')        
            }
            return token ? (
                <h1>你好</h1>
            ) : (
                <div>
                    <button onClick={handleLogin}>请登录</button>    
                </div>
            )
        }
        class GoHome extends React.Component {
            constructor() {
                super();
                this.state = {
                    token:JSON.parse(localStorage.getItem("token")),
                    main:{
                        name:"小明",
                        age: 20
                    }
                }
                this.handleLogin = this.handleLogin.bind(this);
            }
            handleLogin() {
                localStorage.setItem("token", JSON.stringify(this.state.main))
                this.setState({
                    token: JSON.parse(localStorage.getItem("token"))
                })
            }
            render() {
                let {token} = this.state;
                return token ? (
                    <h1>已登录</h1> 
                ) : (
                     <div>
                        <h1>请注册</h1>
                        <button onClick={this.handleLogin}>你好，请登录</button>  
                    </div>
                )                
            }
        }
        root.render(<App/>)
    </script>
</body>
</html>