Reactjs this.state giving Uncaught TypeError: Cannot read property 'groupsData' of null

Question

I am doing 2 basic ajax calls to 2 different apis in one of my ReactJs components. Although, when running the call (on urls I know for certain are working and returning data), I receive:

Uncaught TypeError: Cannot read property 'groupsData' of null

Here is the single component:

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')
                );

Is there something obvious I am missing in terms of reactJS/ ajax?

Answer 1

More actual answer, dependent from used standart:

ES6 Classes

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

ES7+ Classes

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

Answer 2

You should add getInitialState method to your component, where you should set initial state

var BrowseWidgetBox = React.createClass({
   getInitialState: function () {
      return {groupsData: {}, itemsData: {}};
   },
   // your code
});