Subj : Re: [spidermonkey] getter/setter for all properties of an object
To   : franck
From : Brendan Eich
Date : Fri Aug 05 2005 11:45 am

franck wrote:
> Hello,
> 
> I am tring to make a little object that allows me to listen all 
> properties get and set of an object ( a kind of super watch ).
> All is working properly, however I noticed that even if I defined my own 
> setProperty, the property is stored in the object ( I can see it using a 
> for-in loop ).


If you don't want a property to be enumerated by a for-in loop, you must 
define it without the JSPROP_ENUMERATE attribute.  In your example, you 
set obj.foo = 1234, which makes an enumerable property, per ECMA-262. 
You would have to add a resolve hook that defines the property id being 
resolved with 0 attributes to avoid this.

If you want to avoid storing the last-got or last-set value in a slot 
(the normal storage for a property value, allocated by default), you 
would want to use JSPROP_SHARED as the attributes when resolving.

If you wish to resolve only when the id is being assigned to, you want 
JSCLASS_NEW_RESOLVE, and in your JSNewResolveOp, define that id only if 
JSRESOLVE_ASSIGNING.

/be

.