Subj : Re: Enumeration of extended properties of Array and Object prototypes
To   : Chris Zumbrunn <chris@deployzone.com>
From : Brendan Eich <brendan@meer.net>
Date : Fri Mar 19 2004 07:00 pm

Chris Zumbrunn wrote:
> Brendan Eich wrote:
> 
> 
>>Chris Zumbrunn wrote:
>>
>>>I understand that in accordance with the ECMA specs both Spidermonkey 
>>>and Rhino make that additional methods added to Objects are enumerated 
>>>in Javascript for/in loops. 
>>
>>What do you mean, exactly?  Can you give an example?
>>
>>/be
> 
> 
> Array.prototype.foo = "bar";
> var a = new Array(1,2,3);
> for (var i in a) {x += i}
> 
> x is 123foo, but I'd want it to be 123

ECMA dictates that it should be "123foo".

Did you mean that native code defined 'foo' as some kind of built-in? In 
that case, the native code can use ECMA DontEnum, or in SpiderMonkey 
terms, can not use JSPROP_ENUMERATE.

If you mean exactly what you show as an example, then there's no way any 
conforming implementation can avoid enumerating 'foo'.

/be

.