How can I override a method in Javascript and apply it to the original object, not a child?

Question

I'm trying to override the play() method of the Audio object, but I don't want to do so just for a child object. I want to apply it to the standard Audio object.

The problem is I also want to use the original play() method. I've tried cloning the Audio object, making the changes, while calling the original Audio object's play() method and re-assigning back to the original Audio object. It doesn't work.

Ideas anyone? As an example, how could you add an alert() in the play() method while still calling the original play method?

plz. I need to do this because I have calling code generated by a tool that is calling new Audio. So it will be a super pain to constantly have to do a replace-all on this for the hundreds of code generations I'm doing.

Can we see the code you tried? :-)

Florian Margaine
– Florian Margaine

2012-06-12 07:15:10 +00:00
Commented Jun 12, 2012 at 7:15 — Florian Margaine
– Florian Margaine, Commented Jun 12, 2012 at 7:15

abuduba · Accepted Answer · 2012-06-12 07:25:53Z

5

Audio.prototype.play = ( function( old ) {
   var a=1, b=2, c=3; // your 'private' variables - if needed;
   return function() {
      console.log( a+b+c );// do something   
      return old.apply( this, arguments );// return 'original' results
   }
} )( Audio.prototype.play );

answered Jun 12, 2012 at 7:25

abuduba

5,0637 gold badges29 silver badges43 bronze badges

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

Comments

Florian Margaine · Accepted Answer · 2012-06-12 07:19:54Z

4

Basically this could be done like this:

var playOriginal = Audio.prototype.play;
Audio.prototype.play = function(){
    playOriginal.apply(this, arguments);
}

But I'm not sure this will work for all browsers. Extending of native JS object is not recommended in most cases.

edited Jun 12, 2012 at 7:19

Florian Margaine

61.2k15 gold badges94 silver badges120 bronze badges

answered Jun 12, 2012 at 7:16

bjornd

23k4 gold badges59 silver badges74 bronze badges

Comments

jfriend00 · Accepted Answer · 2012-06-12 07:26:21Z

0

You can save the original play method, then replace the play method with a new method that can call the original method whenever it wants to.

Audio.prototype.playOriginal = Audio.prototype.play;
Audio.prototype.play = function(){
    this.playOriginal.apply(this, arguments);
}

answered Jun 12, 2012 at 7:26

jfriend00

711k104 gold badges1.1k silver badges1k bronze badges

Collectives™ on Stack Overflow

How can I override a method in Javascript and apply it to the original object, not a child?

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related