On Thu, Apr 18, 2013 at 9:14 AM, Kevin Smith <[email protected]> wrote: >>> Also, can someone point me to a real-world example of delayed rejection >>> handling? >> >> 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 >> personally. > > > 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 > resolver.reject("error"); > > // 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. ~TJ _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
