Assigning Object in function to Variable or call setState w/o this?

Question

I'm sure this is rather simple, but with me being new to JS and React I can't seem to find an answer to this.

Basically, I have a function that uses the JQ animate method to act as a counter of sorts. The function looks like this:

$({countNum: 99}).animate({countNum: 1000}, {
     duration: 2000,
     easing:'linear',
     step: function() {
      var counter = Math.floor(this.countNum)
      console.log(counter)
     },
     complete: function() {
       return 'counter done';
     }
 });

I am trying to setState within the step so that I can simulate a counter on my app as it counts up to a specific number. In order to set the state I need to bind this to the object in the animate function, however then I can't figure out how to access the countNum so that it increases.

Any ideas? Or am I approaching this totally wrong.

`$({countNum: 99})` is totally wrong. Read the jQuery API again please. — Praveen Kumar Purushothaman, Feb 08 '16 at 09:44
[This question](http://stackoverflow.com/questions/20279484/how-to-access-the-correct-this-context-inside-a-callback) should give you some good insights. May even be a duplicate, if you tidy yours up a bit to make it a bit clearer. — James Thorpe, Feb 08 '16 at 09:48
To access `countNum` in the `step` callback, you can use [one of these techniques](http://stackoverflow.com/a/9324325/607874) — Jose Rui Santos, Feb 08 '16 at 09:59
@PraveenKumar No, it's not wrong. You can use `animate` to animate object properties. You might want to check the link from my previous comment. — Jose Rui Santos, Feb 08 '16 at 10:03

score 1 · Accepted Answer · answered Feb 08 '16 at 09:46

1

You can assign "this" to a specific variable before entering in your callback

var _mythis = this;

and then use "_mythis" to call member function/variable

_mythis.myJQfct();

But I'm not sure it's what you need to do in your case.

answered Feb 08 '16 at 09:46

Marc

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I knew this and I didn't even think to try it. Thanks for the reminder :). Got it working. – Elliott McNary Feb 08 '16 at 09:50

Assigning Object in function to Variable or call setState w/o this?

1 Answers1