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>
        );
    }
}
Apr 27, 2020 in Java-Script by kartik
• 37,530 points
226 views

1 answer to this question.

0 votes

Hello kartik,

You dont have to bind anything, Just use Arrow functions like this:

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

        this.state = {
            count: 1
        };

    }
    //ARROW FUNCTION
    delta = () => {
        this.setState({
            count: this.state.count++
        });
    }

    render() {
        return (
            <div>
                <h1>{this.state.count}</h1>
                <button onClick={this.delta}>+</button>
            </div>
        );
    }
}

Thank You!!

answered Apr 27, 2020 by Niroj
• 82,820 points

Related Questions In Java-Script

0 votes
1 answer

How to Scroll to the top of the page using JavaScript?

Hii @kartik, Using javascript <script> $("a[href='#top']").click(function() { ...READ MORE

answered Apr 2, 2020 in Java-Script by Niroj
• 82,820 points
196 views
0 votes
1 answer

Error: Use of const in strict mode

Hello, If this is happening in nodejs, it ...READ MORE

answered Apr 24, 2020 in Java-Script by Niroj
• 82,820 points
1,557 views
0 votes
1 answer

Cannot install NodeJs: /usr/bin/env: node: No such file or directory

Hii, If you already have nodejs installed (check ...READ MORE

answered May 5, 2020 in Java-Script by Niroj
• 82,820 points
2,620 views
0 votes
1 answer

How to get the directory of the currently running file?

Hello @kartik, This should do it: import ( ...READ MORE

answered May 6, 2020 in Java-Script by Niroj
• 82,820 points
316 views
0 votes
1 answer

What are the vulnerability related to PHP Form?

Hii, The $_SERVER["PHP_SELF"] variable can be used by ...READ MORE

answered Feb 13, 2020 in PHP by Niroj
• 82,820 points
615 views
+1 vote
1 answer

How can we send message multiple time to a specific person or group in whatsapp using loop?

Hii @kartik,  This is simple task to send single ...READ MORE

answered Feb 28, 2020 in Java-Script by Niroj
• 82,820 points
3,094 views
0 votes
1 answer

What is meant by passing the variable by value and reference in PHP?

Hello, When the variable is passed as value ...READ MORE

answered Mar 27, 2020 in PHP by Niroj
• 82,820 points
790 views
0 votes
1 answer

Connection with MySQL server using PHP. How can we do that?

Hey @kartik, You have to provide MySQL hostname, ...READ MORE

answered Mar 27, 2020 in PHP by Niroj
• 82,820 points
244 views
0 votes
1 answer

Uncaught TypeError: Cannot read property 'indexOf' of undefined

Hello @kartik, First of all, you don't need ...READ MORE

answered Jun 2, 2020 in Java-Script by Niroj
• 82,820 points
6,920 views
0 votes
1 answer

Uncaught TypeError: Cannot use 'in' operator to search for '324'

Hello @kartik, You have a JSON string, not ...READ MORE

answered Jun 18, 2020 in Java-Script by Niroj
• 82,820 points
4,232 views