On Nov 28, 2012, at 6:40 PM, Andrea Giammarchi wrote:
> This was not true at some point, but now it seems to be the case in every
> browser.
>
> Just
> Object.prototype.get = function(){};
>
> and any further attempt to use Object.defineProperty(obj, key, {value:123})
> will fail because defineProperty checks inherited get property, or set, and
> these cannot be used together with value ...
>
> Is this a bug or kinda a joke ?
It's what the ES5/5.1 spec says. this is the first time I've seen this raised
as an issue and as far as I know it was always been that way.
It conceivably could be changed to only check own properties but I wonder if
that might not break more code than that which actually has this problem.
There are at least semi-plausable reasons why you might want to intentionally
use inherited properties in a property descriptor:
var defaultDataProperty = {enumerable: true, configurable: true, writable:
true};
Object.defineProperty(obj,key, Object.create(defaultDataProperty, {value: 123});
Who knows whether anybody does things like this.
You can protect yourself against exposure to such Object.prototype attacks by
using patterns like:
Object.defineProperty(obj,key,Object.create(null, {value: 123};
Allen
>
> Scary stuff, IMHO, thanks for clarifications.
>
> br
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