Error: Cannot read property of null

Question

CODE:

var Game = createReactClass({

    getInitalState() {
        return {
            start: false
        }                    
    },

    handleStartClick() {
        this.setState({
            start: true
        })
    },

    handleStopClick() {
        this.setState({
            start: false
        })
    },

    render() {
        return (
            <div>
                <h1>React.js Game of Life</h1>
                <div className="buttons">
                    <button className="btn btn-danger" onClick={this.handelStopClick}>Stop</button>
                    <button className="btn btn-success" onClick={this.handelStartClick}>Start</button>
                </div>
                <Board start={this.state.start}/>
            </div>
        )
    }

});

QUESTION:

Here is the error I get:

Cannot read property 'start' of null

If I change this.state.start to this.props.start, the error goes away but the board does not render.

How can I resolve this situation ?

Mayank Shukla · Accepted Answer · 2017-04-22 15:33:10Z

3

Issue is, you have a spelling mistake, Instead of getInitalState use getInitialState, that's why, you are getting that error:

Cannot read property 'start' of null

Use this, it will work:

getInitialState() {
    return {
        start: false
    }                    
},

answered Apr 22, 2017 at 15:33

Mayank Shukla

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Comments

Panther · Accepted Answer · 2017-04-22 15:37:10Z

0

Your state object is null. This is because you have typo in your function name. The function name should be getInitialState. Then your state would have the default value of start:false

answered Apr 22, 2017 at 15:37

Panther

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