Cannot access the variable set in class constructor

Question

I am having a very frustrating issue. I set my variable in constructor like this:

export class ChannelTransition{
    constructor(props) {
        this.transitionHandler=props;
    }

    channelTransitionSetup(channelsList) {
        console.log(this.transitionHandler.handleHeaderTransition);            
    }
}

And now when I try to access that variable set on constructor I get undefined. I know it has sth to do with scope but then how can I access my variable in constructor?

Make sure your transitionHandler has a property called handleHeaderTransition? Otherwise this is correct. — Thusitha
– Thusitha, Commented Sep 28, 2017 at 13:11
Does props has any property named handleHeaderTransition? Did you debugged the code? What values did you get in the constructor for transitionHandler after setting it? what values are you getting inside channelTransitionSetup for transitionHandler before calling this.transitionHandler.handleHeaderTransition? — palaѕн
– palaѕн, Commented Sep 28, 2017 at 13:14
First I make an object of the class and then I call channelTransitionSetup. So I am sure I am calling it properly. Even when I use console.log in constructor I am able to see the right result — Hamed Minaee
– Hamed Minaee, Commented Sep 28, 2017 at 13:14
@palaѕн Yes it has and even I am able to see it in constructor but in the function maybe because of this scope it returns undefined — Hamed Minaee
– Hamed Minaee, Commented Sep 28, 2017 at 13:15

Antonio Campos · Accepted Answer · 2017-09-28 13:17:15Z

1

This works out for me:

    class ChannelTransition{
        constructor(props) {
            this.transitionHandler=props;
        }
        channelTransitionSetup(channelsList) {
            console.log(this.transitionHandler.handleHeaderTransition);

        }

    }


    let test = new ChannelTransition({handleHeaderTransition:'Ok!'});

    test.channelTransitionSetup();
/* This print 'Ok!' in console */

So I do not know what is your problem. Can you explain how do you use it?

answered Sep 28, 2017 at 13:17

Antonio Campos

1065 bronze badges

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

4 Comments

Hamed Minaee Over a year ago

Thanks for answering: here is how I am calling it: let channelTransition = new ChannelTransition(this.props.handleHeaderTransition); channelTransition.changeChannelOnScroll(channelNames); and then in changeChannelOnScroll I have this.channelTransitionSetup(channelsList);

Hamed Minaee Over a year ago

Also I just simplified the above code and there is a reason that I do not use the channelTransitionSetup directly

Hamed Minaee Over a year ago

I think I found the issue . Your example helped me a lot. So I was going one too many level down in the object hierarchy. Instead if I call it this way it works: this.transitionHandler() instead of this.transitionHandler.handleHeaderTransition(). Thanks for the help

Antonio Campos Over a year ago

It's a pleasure. If you get any other problem just ask over here :)

Collectives™ on Stack Overflow

Cannot access the variable set in class constructor

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related