项目入口文件的代码如下

  1 import React from 'react';
  2 import CommentBox from './Components/CommentBox';
  3 
  4 
  5 function main(){
  6     React.render(
  7         <CommentBox url="./comments.json" pollInterval={2000} />,
  8          document.getElementById('app')
  9     );
 10 }
 11 
 12 main();

CommentBox的代码如下

import React from 'react';
import CommentList from './CommentList';
import CommentForm from './CommentForm';
import $ from 'jquery/src/core';

export default class CommentBox extends React.Component{
    loadCommentsFromServer(){
        $.ajax({
            url: this.props.url,
            dataType: 'json',
            success: function(data){
                this.setState({data: data});
            }.bind(this),
            error: function(err){
                console.err(this.props.url,status,err.toString())
            }.bind(this)
        });
    };  
    getInitialState(){
        return {data: []};    
    };  
    componentDidMount(){
        this.loadCommentsFromServer();
        setInterval(this.loadCommentsFromServer,this.props.pollInterval);
    };  
    render(){
        return(
            <div className="commentBox">
              <h1>Comments</h1>
              <CommentList data={this.state.data} />
              <CommentForm />
            </div>
        );
    }   
};

CommentList的代码如下

import React from 'react';
import Comment from './Comment';

export default class CommentList extends React.Component{
    render(){
        var commentNodes = this.props.data.map(function(comment){
            return(
                <Comment author={comment.author}>
                  {comment.text}
                </Comment>
            );
        });
        return(
            <div className="commentList">
              {commentNodes}
            </div>
        );
    }   
}

Comment的代码如下

import React from 'react';
import Showdown from 'showdown';

var converter = new Showdown.Converter();

export default class Comment extends React.Component{
    render(){
        return(
            <div className="comment">
              <h2 className="commentAuthor">
                {this.props.author}
              </h2>
              {converter.makeHtml(this.props.children.toString())}
            </div>
        );
    }   
}

在浏览器访问的时候却得到如下的结果

• • Uncaught TypeError: Cannot read property ‘data’ of null * * 是我的请求路径有问题还是代码哪里写错了！求大神解答