Uncaught TypeError: Cannot read property 'state' of undefined

Question

I am trying to change from React.createClass to React.Component, but I am getting below error.

Uncaught TypeError: Cannot read property \'state\' of undefined 
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Answer 1

You need to bind your onSelect to the class in the constructor:

constructor(props) {
    super(props);
    this.state = {
        selected: props.selected // use props, not this.props
    };
    this.onSelect = this.onSelect.bind(this);
}

The extends syntax no longer has autobinding like createClass did.

• http://reactkungfu.com/2015/07/why-and-how-to-bind-methods-in-your-react-component-classes/
• https://facebook.github.io/react/docs/handling-events.html