On Sunday, July 27, 2014, Tab Atkins Jr. <jackalm...@gmail.com> wrote:
> On Sat, Jul 26, 2014 at 11:36 AM, Kevin Smith <zenpars...@gmail.com > <javascript:;>> wrote: > >> * As far as I can tell, `hasOwnProperty` is mainly used to implement > maps > >> via objects. `Map` will eliminate this use case. > > > > To a certain extent yes, but not completely. Objects-as-maps will still > be > > used quite frequently as object literals passed into functions (as an > > options object, for example). > > In that case, though, you don't want to use `hasOwnProperty`; you want > to allow property bags to express properties on the proto (for > example, as getters). So this particular use-case of objects-as-maps > is irrelevant for the question at hand. > > > I think that there is still a need here. Since we are really interested > in > > *keys*, what about this: > > > > Object.hasKey(obj, someKey); > > > > which would be a more ergonomic and efficient way of saying: > > > > Object.keys(obj).some(key => key === someKey) > > This is identical to `obj.key !== undefined`, As long as "key" is enumerable. Rick > unless you're allowing > undefined to be passed explicitly as a valid argument for some reason. > > ~TJ > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org <javascript:;> > https://mail.mozilla.org/listinfo/es-discuss >
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