[whatwg] Proposal: createImageBitmap should return a "Promise" instead of using a callback
ian at hixie.ch
Wed Jul 17 17:00:08 PDT 2013
On Wed, 17 Jul 2013, Justin Novosad wrote:
> On Wed, Jul 17, 2013 at 6:54 PM, Ian Hickson <ian at hixie.ch> wrote:
> > On Thu, 18 Jul 2013, Silvia Pfeiffer wrote:
> > > At the same time, I think we should follow a clear pattern for
> > > introducing a Promise based API, which the .create() approach would
> > > provide.
> > I don't understand what that means.
> I think the concern is about the case where we end up with legacy
> callback Factory methods that co-exist new with Promise-based flavors of
> the factory methods. There's no technical obstacle to having the two
> co-exist with the same name, it's just an overload.
I guess I don't understand what methods we're talking about here. Can we
be more concrete? I am very much in favour of not having redundant APIs,
not having lots of different kinds of APIs. But I'm not aware of this
problem existing here. We have constructors and synchronous factory
methods, have had for over a decade, and we're slowly adding constructors
where it makes sense and not adding new synchronous factory methods. But
in the case of ImageData, we need an asynchronous factory. This is unusual
in the Web; mostly we have instead returned incomplete objects. In this
case, the whole point of the API is to avoid this. This means we need a
callback mechanism; Promises are a good, non-invasive way to do this.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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