摘要：index.js import React, { Component } from 'react' import ReactDOM from 'react-dom' class Bar extends Component { constructor() { super() this.state = 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' const UserNameInput = ({ getName }) => { return ( <input onInput={function (e) { g 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' const element = <h1>hello</h1> // 这是一个 React 元素 ReactDOM.render(element, document. 阅读全文

摘要：App.jsx import React from 'react' class App extends React.Component { render() { return <h3>Hello</h3> } } export default App index.js import React fr 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' function Name({ name }) { return <span style={{ color: 'tomato' }}>{name}</span> } 阅读全文

摘要：事件监听函数内部使用 this 会报错，原因是 this 的指向变成了事件触发对应的 DOM 节点，因此需要固定 this，方法有三种： index.js import React from 'react' import ReactDOM from 'react-dom' class Counter 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' function render() { const element = <h1>{new Date().toLocaleTimeString()}</h1> Rea 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' class Clock extends React.Component { constructor() { super() this.state = { time: 阅读全文

摘要：index.js import React, { Component } from 'react' import ReactDOM from 'react-dom' class App extends Component { clickHandler = name => { alert(name) 阅读全文

摘要：index.js import React from "react"; class App extends React.Component { render() { return <h1>Hello, World!</h1>; } } 阅读全文

摘要：yarn yarn create react-app my-app 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' class ANumber extends React.Component { constructor() { super() this.state = { num 阅读全文

摘要：index.js import React from 'react' import ReactDOM from 'react-dom' class Btn extends React.Component { render() { return <button onClick={() => alert 阅读全文

摘要：rt. 阅读全文