>
>> We could even allow for direct proxies to acquire non-standard internal
>> properties from their target object. This could be a useful principle when
>> wrapping host objects.
>
> This seems important in order to make host methods work, e.g., the ones that
> access the [[Value]] property. I guess you could code around it by proxying
> those methods as well?
>
> What's the [[Value]] property? I'm not sure I understand.
Er, sorry, [[PrimitiveValue]]. (It was called [[Value]] in Edition 3.) Section
8.6.2, Table 9.
> But I have some serious reservations about it. For one, tying the notion of
> "becomeability" to extensibility seems sub-optimal. I'm not sure you always
> want an object to be non-extensible when you want it to be non-becomeable.
> And a serious practical issue is whether host objects could be becomeable.
> I'm pretty sure that's going to be a serious problem for implementations.
>
> I agree in principle that "attachability" or "becomeability" is distinct from
> extensibility. But from a usability POV, what's the alternative? To introduce
> yet another bit, and to put the onus on defensive objects by requiring them
> to do Object.freeze(Object.cantTrap(myObject))? To me, that seems worse than
> tying non-extensibility to non-becomeability.
One alternative is not to include Proxy.attach. :)
But I need to think about this more; I'm not sure those are the only options.
Maybe they are. You've had more time to think about this than I have. :)
>> It’s still as easy to create such “virtual” proxies: just pass a fresh empty
>> object (or perhaps even null?)
>
> Please, make it null. So much more pleasant (and avoids needless allocation).
>
> (The only downside of allowing null to mean "no target" would be if you
> wanted to future-proof for virtualizable primitives, including a
> virtualizable null.)
>
> Avoiding needless allocation is why I proposed null, indeed. But there are
> some unresolved issues here: if the target is null, how should the proxy
> determine its typeof, [[Class]] and [[Prototype]]?
"object", "Object", and null. :)
> This needs more thought.
Sure, I can believe that. But as long as there are reasonable defaults for all
these things, I would much prefer to allow null.
> IMHO, if we would buy into direct proxies, I see no need to continue
> supporting Proxy.create{Function}.
Agreed.
Dave
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