Extending Object.prototype JavaScript

Question

I am not asking if this is okay:

Object.prototype.method = function(){};

This is deemed evil by pretty much everyone, considering it messes up for(var i in obj).

The Real Question

Ignoring

• Incompetent browsers(browsers that don't support Object.defineProperty)
• Potential for property collision or overriding

Assuming you have some incredibly useful method, is this considered wrong/unethical?

Object.defineProperty(Object.prototype, 'methodOnSteriods',{
  value: function(){ /* */ },
  writable: true,
  configurable: true,
  enumerable: false
});

If you believe the above is unethical, why would they even implement the feature in the first place?

Answer 1

UPDATE from 2021

Despite this being the accepted answer, 10 years of experience has taught me this isn't the best idea. Pretty much anything you can do to avoid polluting the global scope is a very very good thing.

Original answer below, for posterity, and because stack overflow will not let me delete an accepted answer.

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Original answer from 2011

I think it's fine if it works in your target environment.

Also I think prototype extension paranoia is overblown. As long as you use hasOwnProperty() like a good developer that it's all fine. Worst case, you overload that property elsewhere and lose the method. But that's your own fault if you do that.