Promise.cast and Promise.resolve
brendan at mozilla.com
Tue Jan 28 12:48:58 PST 2014
Domenic Denicola wrote:
> From: es-discuss<es-discuss-bounces at mozilla.org> on behalf of Brendan Eich<brendan at mozilla.com>
>> > Quildreen Motta wrote:
>>> >> If that's correct, I don't see any use cases for Promise.resolve right now, unless a library where to provide a corresponding unspecified `flatMap` implementation.
>> > IIRC (and I may not; endless promises threads make me sleepy) this is the reason to have Promise.resolve: to enable some to blaze the flatMap trail ahead of ES6.
> Kind of. Since `Promise.resolve(x)` is just `new Promise(resolve => resolve(x))`, the only reasons for including that shorthand method are symmetry and the idea that this operation might be common enough to necessitate a shorthand. See my earlier reply.
> On the other hand, that*is* part of the reason we moved all the unwrapping to the `then` side---as Mark puts it, using the "accept" operation instead of "resolve," albeit while still using the "resolve" name. (Which is pretty confusing when you try to explain it, but I swear, it makes sense...)
I buy it.
Paolo may not. Mozilla XUL JS does seem full of .resolve calls, some of
which might want to be .cast calls instead.
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