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javascriptgoogle-chromeprototype-programmingprototyping

Extending Object's prototype has weird behavior in Chrome

Can anyone please explain why this code behaves so weird under Google Chrome:

<script>
console.log({someproperty:'hello'}) ;
Object.prototype.get = function(){} ;
</script>

The content of the object printed in the console has no "someproperty", instead it has a "get someproperty" which is a function.
I'm using Chrome 21.0.

Is this expected? Is it a bug?

Solution

  • I can't explain to you why setting Object.prototype.get to something different causes such odd behavior, except that that function is almost certainly what Chrome/Webkit is using behind the scenes to generate its fancy object logging.

    I can tell you that the reason it's happening even though you're setting .get after the console.log is that Chrome/Webkit doesn't retrieve the object until you actually click the arrow in the console to expand the object. You can test this by running this jsfiddle: http://jsfiddle.net/BNjWZ/

    Notice that if you click the arrow to expand the object right away, the object will look normal, but if you wait three seconds for the .get = function(){}; to be called, it will have the 'get's.

    I'm seeing this behavior (both the odd 'get' in the object display and the delayed object logging) in 22.0.1229.79