More flexibility in the ECMAScript part?
Tab Atkins Jr.
jackalmage at gmail.com
Thu Apr 18 09:43:56 PDT 2013
On Thu, Apr 18, 2013 at 9:14 AM, Kevin Smith <zenparsing at gmail.com> wrote:
>>> Also, can someone point me to a real-world example of delayed rejection
>> What do you mean by "delayed"? If that is: a promise has been rejected and
>> someone later add a .fail/.catch handler to it, then I've never done that
> Yes, that's what I mean. Specifically, a real-world example where the
> rejection handler is added in "some future turn", using a fuzzy definition
> of that phrase. A contrived example would be:
> // Create a future and get the resolver
> let resolver, future = new Future(r => resolver = r);
> // Reject it
> // Attach a rejection handler 5 seconds later
> setTimeout(() => future.then(null, err => null), 5000);
There are several DOM APIs planning to use Futures which will return
the same future across multiple calls. This future may have been
rejected in a previous turn.
An example of this is the Font Load API built with Futures that I'm
currently proposing: <http://www.xanthir.com/b4PV1>. The Font#ready
function tracks the loading status of a single @font-face rule, so it
just returns the same future over and over.
These kinds of APIs *could* be done by tracking future state
internally, and always returning a fresh future matching the internal
state, but that seems silly.
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