Object.mixin rather than Object.getOwnPropertyDescriptors

[Andrea Giammarchi]

IMO every time you use `getOwnPropertyDescriptor` over a
`getOwnPropertyNames` you are asking for a `getOwnPropertyDescriptors`
implementation, that's the use case.

Twisting your question, do you have any use case for `getOwnPropertyNames`
that won't require later on `getOwnPropertyDescriptor` ?


On Tue, Apr 22, 2014 at 11:59 AM, Claude Pache <claude.pache at gmail.com>wrote:

>
> Le 22 avr. 2014 à 19:58, Andrea Giammarchi <andrea.giammarchi at gmail.com>
> a écrit :
>
> > while I think that
> > Object.create(
> >
> >
> > Object.getPrototypeOf(originalObject),
> >
> >
> > Object.getOwnPropertyDescriptors(originalObject)
> > )
> > looks semantically better than
> > Object.mixin(
> >
> >
> > Object.create(Object.getPrototypeOf(originalObject)),
> >
> >   originalObject
> >
> > )
> > I also think that Object.mixin could be used for similar cases but I am
> not sure if:
> >       • is able to mixin also not enumerable and Symbols
>
> When it was still in the ES6 draft, `Object.mixin` *did* copy all own
> properties.
>
> >       • performs some unrequired magic such rebinding getters and
> setters that should not happen or actually does not make sense to me
>
> My feeling is that in most cases where that magic is not required, it is
> also not very important. Or there could be an option for enabling/disabling
> that functionality, for that would seem better to me than two wildly
> different ways for getting almost the same result.
>
> > The reason such long method name has been proposed was for symmetry with
> defineProperties and as meaningful plural version that should not exclude
> Object.mixin
> >
> > Long story short, when mixin is needed, use mixin, otherwise when all
> descriptors are needed, use getOwnPropertyDescriptors?
>
> Do you have cases where getting all descriptors is used for something else
> than setting them immediately to another object? My point is that I don't
> see the added value of `Object.getOwnPropertyDescriptiors` once you have a
> correctly designed `Object.mixin`-like method.
>
> —Claude
>
>
> >
> > In few words I don't see how having both could hurt anyone
> >
> >
> >
> >
> > On Tue, Apr 22, 2014 at 10:27 AM, Claude Pache <claude.pache at gmail.com>
> wrote:
> > Hi,
> >
> > There has been request to add `Object.getOwnPropertyDescriptors`
> (plural) to the standard. Reviewing use cases presented in thread [1] or in
> older thread [2], it seems to me that all of them boil down to copy all own
> properties of one object to another, e.g.,
> >
> >     Object.defineProperties(target,
> Object.getOwnPropertyDescriptors(source))
> >     Object.create(proto, Object.getOwnPropertyDescriptors(source))
> >     // etc.
> >
> > However, this is exactly what `Object.mixin` (deferred from ES6) was
> designed for:
> >
> >     Object.mixin(target, source)
> >     Object.mixin(Object.create(proto), source)
> >     // etc.
> >
> > Besides being shorter to write, `Object.mixin` has the advantages of (1)
> not creating an intermediate object; (2) taking care of some subtleties,
> like rebinding `super` for methods, getters and setters if needed.
> >
> > Therefore, I think that `Object.mixin` is a better function to have than
> `Object.getOwnPropertyDescriptors`.
> >
> > —Claude
> >
> >
> > [1] http://esdiscuss.org/topic/object-getownpropertydescriptors-o-plural
> > [2] http://esdiscuss.org/topic/object-getownpropertydescriptor
> > _______________________________________________
> > es-discuss mailing list
> > es-discuss at mozilla.org
> > https://mail.mozilla.org/listinfo/es-discuss
> >
>
>
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