React学习笔记3：用es2015（ES6）重写CommentBox

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在一开始的时候webpack配置中我们就加入了es2015的支持，就是下面的配置，但之前的学习笔记都使用的es5完成，所以专门作一篇笔记，记录使用es6完成CommentBox

query: {
  presets: ['es2015','react']
}

1、创建相关文件

touch src/commentEs6.js
//修改webpack，增加该入口文件
  entry:{
    'index':'./src/index.js','comment':'./src/comment.js','commentEs6':'./src/commentEs6.js',},//修改build/index.html，引入该文件
  <script src="commentEs6.js"></script>

2、做个简单的测试，看下浏览器

//require全部用import来完成
import React from 'react';
import ReactDom from 'react-dom';
//es6支持类，通过类继承完成组件的开发
class CommentBox extends React.Component {
    render () {
        return <div>Hello World</div>
    }
}

//渲染
ReactDom.render(
    <CommentBox />,document.getElementById('content')
)

3、直接贴出完整修改后的代码

import React from 'react';
import ReactDom from 'react-dom';
import marked from 'marked'
import $ from 'jquery'

class CommentBox extends React.Component {
    constructor(props){
        super(props)
        //state 初始化直接在构造函数完成
        this.state = {data:[]}
    }
    //函数的书写方式也发生了变化
    loadCommentsFromServer(){
        //还不太明白，总之this到了ajax中指向的对象就发生了变化
        var url = this.props.url
        $.ajax({
            url:url,dataType:"json",cache:false,//利用箭头函数传参，可以少去了bind this
            success:(data) => {
                this.setState({data: data})
            },error:(xhr,status,err) => {
                console.log(url,err.toString())
            }
        })
    }
    handleSubmitComment(data){
        var url = this.props.url
        $.ajax({
            url:url,type:"POST",data:data,success:(data) => {
                this.setState({data:this.state.data.concat(data)});
            },err) => {
                console.log(this.props.url,err.toString())
            }
        })
    }
    componentDidMount(){
        this.loadCommentsFromServer()
        //setTimeout(this.loadCommentsFromServer,2000)
    }

    render() {
        return (
            <div className='commentBox'>
                <h1>Comments</h1>
                <CommentList data={this.state.data} />
                <CommentForm onSubmitComment={this.handleSubmitComment.bind(this)} />
            </div>
        )
    }
}


class CommentList extends React.Component{
    constructor(props) {
        super(props)
    }

    render(){
        var commentNodes = this.props.data.map(function(comment){
            return (
                <Comment author={comment.author} key={comment.id}>
                    {comment.text}
                </Comment>
            )
        });
        return (
            <div className='commentList'>
                {commentNodes}
            </div>
        )
    }
}

class Comment extends React.Component {
    constructor(props) {
        super(props)
    }
    rawMarkup(){
        var rawMarkup = marked(this.props.children.toString(),{sanitize:true})
        return {__html:rawMarkup}
    }
    render(){
        return (
            <div className='comment'>
                <h2 className='commentAuthor'>
                    {this.props.author}
                </h2>
                <span dangerouslySetInnerHTML={this.rawMarkup()} />
            </div>

        )
    }
}

class CommentForm extends React.Component{
    constructor(props) {
        super(props)
        this.state = {author:"",text:""}
    }
    handleAuthorChange(event){
        this.setState({author:event.target.value})
    }
    handleTextChange(event){
        this.setState({text:event.target.value})
    }
    handleSubmit(event){
        event.preventDefault();
        var author = this.state.author.trim()
        var text = this.state.text.trim()
        if(!text||!author) {
            return;
        }
        this.props.onSubmitComment({author:author,text:text});
        this.setState({author:"",text:""})
        return false;
    }

    render(){
        return (
            <form className='commentForm' onSubmit={this.handleSubmit.bind(this)}>
                <input type='text' onChange={this.handleAuthorChange.bind(this)}
                       placeholder='怎么称呼您呢？爷' value={this.state.author} />
                <input type='text' onChange={this.handleTextChange.bind(this)}
                       placeholder='爷有什么赐教？' value={this.state.text} />
                <input type='submit' value='提交' />
            </form>
        )
    }
}


ReactDom.render(
    <CommentBox url="http://localhost:8080/api/comment" />,document.getElementById('content')
)

（编辑：李大同）

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