Reactjs this.state给出Uncaught TypeError:无法读取null的属性'groupsData'

Question

我正在我的一个ReactJs组件中对2个不同的api进行2个基本的ajax调用.虽然,在运行调用时(在我确定知道的网址上工作并返回数据),我收到:

Uncaught TypeError: Cannot read property 'groupsData' of null

这是单个组件:

var BrowseWidgetBox = React.createClass({
                getGroupsApi: function(){
                    $.ajax({
                        url: this.props.groupsApi,
                        dataType: 'json',
                        type: 'GET',
                        success: function(groupsData){
                            this.setState({groupsData: groupsData});
                        }.bind(this),
                        error: function(xhr, status, err){
                            console.error(this.props.groupsApi ,status, err.toString());
                        }.bind(this)
                    });

                },
                getItemsApi: function() {
                 $.ajax({
                        url: this.props.itemsApi,
                        dataType: 'json',
                        type: 'GET',
                        success: function(itemsData){
                            this.setState({itemsData: itemsData});
                        }.bind(this),
                        error: function(xhr, status, err){
                            console.error(this.props.groupsApi ,status, err.toString());
                        }.bind(this)
                    });
                },
                componentDidMount: function() {
                    this.getGroupsApi();
                    this.getItemsApi();
                },
                render: function() {
                    return (<div className="BrowseWidgetBox">
                                <MainMenu groupsData={this.state.groupsData} itemsData={this.state.itemsData} />
                                <Display  />
                            </div>);
                }
            });



                React.render(
                    <BrowseWidgetBox groupsApi="/*imagine a working url here*/" itemsApi="/*imagine a working url here*/" />, document.getElementById('widget-container')
                );

在reactJS/ajax方面,我有什么明显的缺失吗？

Answer 1

更多实际答案,取决于使用的标准:

ES6课程

export class Component extends React.Component {
  constructor(props) {
    super(props);
    this.state = { groupsData: {}, itemsData: {} };
  }
  ...
}

ES7 +课程

export class Counter extends React.Component {
  state = { groupsData: {}, itemsData: {} };
  ...
}