Uncaught reference error when I try and make a Javascript object

Question

I'm trying to make a constructor for an addition problem generator but when I run my code I get "Uncaught ReferenceError: firstNum is not defined"

function GenAddProb()
{
    this.firstNum = returnRandomInt(1,10);
    this.secondNum =  returnRandomInt(1,10);
    this.ans = firstNum+secondNum;
}

Is there something wrong with the way my constructor is written? From what I've seen in tutorials I don't have to define firstNum and secondNum as variables before I use them in the constructor.

this.ans = firstNum+secondNum; where you found firstNum and secondNum? — Shaiful Islam
– Shaiful Islam, Commented Oct 29, 2017 at 3:53

Nicholas Tower · Accepted Answer · 2017-10-29 03:44:10Z

4

this.ans = firstNum+secondNum;

As it says, firstNum is not defined. Did you mean this.ans = this.firstNum + this.secondNum?

From what I've seen in tutorials I don't have to define firstNum and secondNum as variables before I use them in the constructor.

You don't need to define this, if that's what you mean. In the context of a constructor, this is the object you're constructing. But if you want to create and use local variables, you'll need to define them.

edited Oct 29, 2017 at 3:44

answered Oct 29, 2017 at 3:39

Nicholas Tower

87k10 gold badges115 silver badges127 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Karim Shoorbajee Over a year ago

I see. So I still have to reference what object I'm using even if it's from within the constructor. Changed it to this.ans = this.firstNum + this.secondNum and it works as intended. Thanks for your help!

Collectives™ on Stack Overflow

Uncaught reference error when I try and make a Javascript object

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related