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?

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?

• javascript

Share Improve this question Follow asked Jan 3, 2012 at 18:58 FluffyFluffy 28.4k4242 gold badges156156 silver badges238238 bronze badges

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2 Answers 2

Sorted by: Reset to default 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).

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.