Uncaught TypeError Cannot read property setState of undefined

0 votes

I am getting the following error

Uncaught TypeError: Cannot read property 'setState' of undefined

even after binding delta in the constructor.

class Counter extends React.Component {
    constructor(props) {
        super(props);

        this.state = {
            count : 1
        };

        this.delta.bind(this);
    }

    delta() {
        this.setState({
            count : this.state.count++
        });
    }

    render() {
        return (
            <div>
                <h1>{this.state.count}</h1>
                <button onClick={this.delta}>+</button>
            </div>
        );
    }
}
May 18, 2020 in CSS by kartik
• 37,510 points
14,107 views

2 answers to this question.

0 votes

Hello,

When using ES6 code in React always use arrow functions, because this context is automatically binded.

so use this:

(videos) => {
    this.setState({ videos: videos });
    console.log(this.state.videos);
};

instead of:

function(videos) {
    this.setState({ videos: videos });
    console.log(this.state.videos);
};

Thank you!!

answered May 18, 2020 by Niroj
• 82,880 points
0 votes

Use

this.delta() = this.delta.bind(this);

in place of this.delta.bind(this);
answered Aug 22, 2020 by Abhishek

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