Cannot read property 'setState' of undefined, inside Object.keys, react

Question

I'm using: method = () => { } so i don't need to bind the function

here's my class:

class Form extends Component {

  constructor(props) {
    super(props);

    this.state = {
      disabledFields: [],
    };

  }

  executeCode = ( methodCode ='', params = {} ) => {
    const result = crudCode[methodCode](params);
    if (result && result.newStates) {

      Object.keys(result.newStates).map(function(keyName, keyIndex) {
          this.setState( {  nada: 'nada' });
        });
    }
  }

I get this error:

TypeError: Cannot read property 'setState' of undefined
> 48 |         this.setState( {  nada: 'nada' });

what I'm doing wrong, I've already used this type of function and setState, but i don't know this time it does not work.

Possible duplicate of How to access the correct `this` inside a callback? — Andrew Li
– Andrew Li, Commented Dec 27, 2017 at 0:52

Davin Tryon · Accepted Answer · 2017-12-27 00:41:01Z

5

You don't use an arrow function in your map callback:

Object.keys(result.newStates).map(function(keyName, keyIndex) {
    this.setState( {  nada: 'nada' });
});

So, it is not bound to this.

This will work instead:

Object.keys(result.newStates).map((keyName, keyIndex) => {
    this.setState( {  nada: 'nada' });
});

answered Dec 27, 2017 at 0:41

Davin Tryon

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1 Comment

Andrew Li Over a year ago

If you don't mind, could you use your gold badge to mark as duplicate?

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