Read access to [[Class]]?

Allen Wirfs-Brock allen at wirfs-brock.com
Sat Jan 28 08:21:43 PST 2012


On Jan 27, 2012, at 10:15 PM, John-David Dalton wrote:

> I noticed in the ES6 draft it states that host objects *do not* have
> the [[NativeBrand]] internal property.
> I think "do not have" should be reworded to "are not required to have".
> This would allow existing inferences like
> `{}.toString.call(window.opera) == '[object Opera]'`.
> 

I probably need to be more explicit about host objects and add another step just before step 5

If O is a host object, let tag be an implementation defined string value. The value may not be "Array", "Boolean", "Date", "Error", "Function", "JSON", "Math", "Number", "Object", "RegExp", and "String".

Also, the definition of Host Object needs to be tighten up to make it clear that an object is only a host object if it has some "magical" behavior. 

Finally, window.opera is really just a normal object it could use my proposed private name based mechanism to set its toString tag.

Allen
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