Override image constructor in JS?

Question

Is it possible to override the Image constructor in JS? So that, for example, every time a new Image() is created, a message is written to the console?

Mateusz W · Accepted Answer · 2012-01-03T19:20:43.627

7

Try this:

(function () {
    var OriginalImage = window.Image;
    window.Image = function (width, height) {
        console.log('New image');
        return new OriginalImage(width, height);   
    }
}());

Not sure if it will work in all browsers.

Anyway it is not best idea to override built in types (unless you want to use it to mock/stub for test purposes).

edited Jan 03 '12 at 19:20

answered Jan 03 '12 at 19:10

Mateusz W

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This worked in FF, only thing I'd add is that the Image object can take in an optional width and height parameter. – patorjk Jan 03 '12 at 19:17
Updated to provide width and height :) – Mateusz W Jan 03 '12 at 19:21

score 2 · Answer 2 · answered Jan 03 '12 at 19:16

2

Take a look at this link, it is possible to override constructors. However, I believe this is now what you want, you want to EXTEND it. Take a look at the "Extends ABC" part.

answered Jan 03 '12 at 19:16

Soph

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Override image constructor in JS?

2 Answers2

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