On Tue, Mar 29, 2011 at 11:58 AM, Scott Sauyet <[email protected]>wrote:
> Mark McDonnell wrote:
> > Essentially I would like to use Promises in the same way
> > as used by jQuery 1.5 (or at least how their AJAX API uses
> > it) but I just don't have the first clue on how to implement
> > it in actual JavaScript code?
>
> I still think you need to work out the API you would like, perhaps
> something like this would be a good start:
>
> Lib:
> when(/*Deferred*/ dfd): Promise
>
> Deferred:
> promise(): Promise
> resolve(/*Whatever*/ args): void, calls 'then' listeners
> reject(/*Whatever*/ args): void, calls 'fail' listeners
>
> Promise:
> then(/*Function*/ fn): Promise, will fire on resolve
> fail(/*Function*/ fn): Promise, will fire on reject
>
> This might be used like this:
>
> var dfd = new Lib.Deferred();
> Lib.when(dfd)
> .then(function(answer) {console.log(answer);})
> .fail(function(x) {console.warn("Oops");});
>
> try {
> var answer = prompt("What is the meaning of life?");
> dfd.resolve(answer);
> } catch (e) {
> dfd.reject(e);
> }
>
> That is, I believe, a simplification of jQuery's API. Is this the
> type of code you're trying to include in your library?
>
Well, not quite. The fail method is redundant as the then method is spec'd
to take both a success and failure callback (jQuery actually extends this to
allow arrays of callbacks for either, but that's unnecessary and outside the
Promises/A spec). Also, I'm not quite sure what you're doing with when here,
but it should take a static library fn, not an instance method.
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