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TypeError: Cannot read property 'setState' of undefined

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Azad Kshitij answered on March 4, 2021 Popularity 10/10 Helpfulness 4/10

answer TypeError: Cannot read property 'setState' of undefined

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related Error in render: "TypeError: Cannot read property 'state' of undefined"

TypeError: Cannot read property 'setState' of undefined

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

      this.state = {
          count : 1
      };

      this.delta = 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>
        );
    }
}

Popularity 10/10 Helpfulness 4/10 Language javascript

Source: Grepper

Tags: javascript undefined

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Contributed on Mar 30 2021

Azad Kshitij

0 Answers Avg Quality 2/10

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Cannot read property 'setState' of undefined

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//  way #1 - recommended
// puting .bind(this) after using the reference 

	<input onChange={this.onInputChange.bind(this)} placeholder="First Name" />
  
// way #2
// adding this line for each method you use
  
  constructor(){
	this.onInputChange = this.onInputChange.bind(this)
  }

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Mar 04 2021

Hjmcoder

0 Answers Avg Quality 2/10

Error in render: "TypeError: Cannot read property 'state' of undefined"

Comment

You should pass a arrow function instead of regular function : const delta=()=>{
this.setState((preCount)=>{
		preCount=this.state.count+1;
    }
}

Popularity 1/10 Helpfulness 1/10 Language javascript

Source: Grepper

Tags: javascript

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Contributed on Jun 25 2021

Funny Flatworm

0 Answers Avg Quality 2/10

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TypeError: Cannot read property 'setState' of undefined

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Cannot read property 'setState' of undefined

Error in render: "TypeError: Cannot read property 'state' of undefined"

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