Undefined in React method

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Undefined in React method

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#1 by (1 votes)

0

When I press the "." to add the decimal, the display goes from "0" to "undefined.". That is, add it but the 0 becomes undefined. I do not understand why.

  state = {
    displayValue:"0",
    operator: null,
    pendingOperation: false,
    newValue: null
  };

inputDot(){
const displayValue=this.displayValue;
  this.setState({
    displayValue: displayValue + "."
  }) 
console.log(this.displayValue)
}

<button type="button"onClick={() => this.inputDot()}>.</button>

reactjs react

asked by Hernan Ariel 31.12.2018 в 23:29

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1 answer

Keyframes in SCSS Error when addressing

score 1 · Answer 1

The problem is that you are accessing the value incorrectly, you want to access this.displayValue , that property does not exist in the component so it is correct to return undefined , what you want to access is the state of the object, so you must prefix state before displayValue , the line would be as follows:

const displayValue = this.state.displayValue;