CODEWITHSUNDEEP
javascriptreactjs
El Fuerst
El Fuerst

Reputation: 93

How to fix 'Cannot read property 'value1' of undefined?

constructor() {
  super();
  this.state = {
    value1 : Math.floor(Math.random() * 100),
    value2 : Math.floor(Math.random() * 100),
    value3 : Math.floor(Math.random() * 100),
    proposedAnswer : Math.floor(Math.random() * 3) + this.state.value1 + this.state.value2 + this.state.value3,
    numQuestions : 0,
    numCorrect : 0
  };
}

I don't understand how it cannot read the value of the variable 'value1'.

Upvotes: 1

Views: 175

Answers (1)

Arnaud Claudel
Arnaud Claudel

Reputation: 3138

The state is still empty when you want to use it.
When you call this.state.value1, it won't refer to the current object but to the state itself, which hasn't been set yet because you're defining it.

You could extract the values as local variables and use them instead.

constructor() {
  super();
  const val1 = Math.floor(Math.random() * 100)
  const val2 = Math.floor(Math.random() * 100)
  const val3 = Math.floor(Math.random() * 100)
  this.state = {
    value1 : val1,
    value2 : val2,
    value3 : val3,
    proposedAnswer : Math.floor(Math.random() * 3) + val1 + val2 + val3,
    numQuestions : 0,
    numCorrect : 0
  };
}

Upvotes: 3

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