1.函数试组件 import React from 'react'; import ReactDOM from 'react-dom'; function Clock(props){ return( <div> <h1>Hello, world!</h1> <h2>It is {props.date.toLocaleTimeString()}.</h2> </div> ); } function tick() { ReactDOM.r…

开关按钮制作   import React from 'react'; import ReactDOM from 'react-dom'; class Toggle extends React.Component { constructor(props) { super(props); this.state = {isToggleOn: true}; // 这个绑定是必要的,使`this`在回调中起作用 this.handleClick = this.handleClick.bind(this)…

const scaleNames = { c: 'Celsius', f: 'Fahrenheit' }; function toCelsius(fahrenheit) { ) * / ; } function toFahrenheit(celsius) { / ) + ; } function tryConvert(temperature, convert) { const input = parseFloat(temperature); if (Number.isNaN(input)) {…

class Reservation extends React.Component { constructor(props) { super(props); this.state = { isGoing: true, numberOfGuests: , value: '' }; this.handleInputChange = this.handleInputChange.bind(this); this.handleSubmit = this.handleSubmit.bind(this);…

function NumberList(props) { const numbers = props.numbers; const listItems = numbers.map((number) => <li key={number.toString()}> {number} </li> ); return ( <ul>{listItems}</ul> ); } , , , , ]; ReactDOM.render( <NumberList n…

import React from 'react'; import ReactDOM from 'react-dom'; class LoginControl extends React.Component { constructor(props) { super(props); this.handleLoginClick = this.handleLoginClick.bind(this); this.handleLogoutClick = this.handleLogoutClick.bin…

import React from 'react'; import ReactDOM from 'react-dom'; function formatDate(date) { return date.toLocaleDateString(); } const comment = { date: new Date(), text: 'I hope you enjoy learning React!', author: { name: 'Hello Kitty', avatarUrl: 'http…

一.state 1.state的作用 state是React中组件的一个对象.React把用户界面当做是状态机,想象它有不同的状态然后渲染这些状态,可以轻松让用户界面与数据保持一致. React中,更新组件的state,会导致重新渲染用户界面(不要操作DOM).简单来说,就是用户界面会随着state变化而变化. 2.state工作原理 常用的通知React数据变化的方法是调用setState(data,callback).这个方法会合并data到this.state,并重新渲染组件.渲染完成后,…

转自http://react-china.org/t/react-js/398的jsgeeker 中文文档地址 http://reactjs.cn GitHub地址 https://github.com/reactjs-cn/react-docs 阮一峰的 "React 入门实例教程" http://www.ruanyifeng.com/blog/2015/03/react.html 极客学院整理的文档 http://wiki.jikexueyuan.com/project/react…

其实在react中实现倒计时的跳转方法有很多中,其中我认为较为好用的就是通过定时器更改state中的时间值. 首先在constructor中设置10秒的时间值: constructor () { super() this.state={ seconds: 10, }; } 然后在componentDidMount中添加定时器: componentDidMount () { let timer = setInterval(() => { this.setState((preState) =>({…