On Fri, Feb 27, 2015 at 7:49 PM, John Lenz <[email protected]> wrote:
> Closure Library's promise implementation supports "cancel": > > > https://github.com/google/closure-library/blob/master/closure/goog/promise/promise.js#L502 > > A promise is cancelled only if all the "child" promises are also cancelled. > I did not say that correctly, a "parent" promise can be cancelled by a "child" it is the only child or all the children cancel. A parent can alway cancel its children (to the children this is simply "reject"). It does add a significant amount of complexity to the promise implementation but it is for the most part contained there. I don't believe that "cancel" can be added after the fact and an alternative (subclass or otherwise) is needed. > > On Thu, Feb 26, 2015 at 11:43 PM, Andrea Giammarchi < > [email protected]> wrote: > >> AFAIK bluebird did: >> >> https://github.com/petkaantonov/bluebird/blob/master/API.md#cancelerror-reason---promise >> >> But I agree once you've made Promises more complex than events ( xhr in >> this case ) nobody wins :-/ >> >> Although, specially for fetch or anything network related, there **must** >> be a way to bloody cancel that! >> >> ....right? >> >> >> On Fri, Feb 27, 2015 at 7:31 AM, Kevin Smith <[email protected]> >> wrote: >> >>> The discussion on that github issue surrounding promise subclassing >>> makes my head spin, especially when it comes to working out how cancelation >>> is supposed to flow through a graph of promise dependencies. We should be >>> wary of adding complexity to the core. >>> >>> The simple way to view the situation is to say that promises are simply >>> transparent containers for asynchronous values. Control capabilities should >>> therefore be represented by a separate abstraction. This will help keep >>> complexity at the edges. >>> >>> Has any library experimented with the cancelation token approach yet? >>> On Feb 27, 2015 1:46 AM, "Anne van Kesteren" <[email protected]> wrote: >>> >>>> As a heads up, there's some debate around the fetch() API how exactly >>>> request termination should work and how that affects promises: >>>> >>>> https://github.com/slightlyoff/ServiceWorker/issues/625 >>>> >>>> The WebRTC WG has also been discussing canceling in the context of >>>> terminating a request for permission from the user. I think they >>>> decided to postpone for now until there's a bit more progress on what >>>> cancelable promises means, but I would not expect everyone to wait >>>> forever. >>>> >>>> >>>> -- >>>> https://annevankesteren.nl/ >>>> _______________________________________________ >>>> es-discuss mailing list >>>> [email protected] >>>> https://mail.mozilla.org/listinfo/es-discuss >>>> >>> >>> _______________________________________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >>> >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> >> >
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