toDeferred suggestion

[wolfflow]

Sometimes, you need to turn your Bacon observable back to $.Deferred (/Promise/etc.).
(e.g. in order to provide a solution for jQuery users which are not familiar with Bacon =) ) and, AFAIK, RxJS has smth similar.

A method suggestion gist is here:
https://gist.github.com/wolfflow/b0a7a9a37938f80a9c6d

[raimohanska]

The idea sounds good. Dependency on jQuery is not acceptable in the core though. Should we consider a more generic asPromise method instead, without ext deps?

The jq deferred based impl can of course be provided as a plugin too.

-juha-

On 8.3.2014, at 22.18, Daniel K [email protected] wrote:

Sometimes, you need to turn your Bacon observable back to $.Deferred (/Promise/etc.).
(e.g. in order to provide a solution for jQuery users which are not familiar with Bacon =) ) and, AFAIK, RxJS has smth similar.

A method suggestion gist is here:
https://gist.github.com/wolfflow/b0a7a9a37938f80a9c6d

—
Reply to this email directly or view it on GitHub.

[wolfflow]

What do you think about Bacon.$.toDeferred(obs) in 'bacon.jquery' ?

Also, there're several platform-dependent implementations of Promises/A (WinJS, 'native' Promises @ webkit, etc..)
Pls, take a look at gist I've made here about promises:
https://gist.github.com/wolfflow/71af0ad215c856291e5c

[raimohanska]

Adding toDeferred in bacon.jquery sounds like a good idea. In fact I'd rather extend the Observable prototype so that stream.toDeferred() would be available.

Don't know yet what to do with all the different promise specs and implementations :)

[wolfflow]

What about putting Bacon.Observable::toDeferred method inside bacon.jquery ?
( And, there is Bacon.Observable::ajax already )

[raimohanska]

Yes, that's exactly what I meant :)

[raimohanska]

So #32 was merged!

Still, we should 1) update README 2) add tests 3) refactor implementation: what is withHandler doing there? Why not plain subscribe?

[wolfflow]

Ok will do. Surely, it must be subscribe)
Once upon a time, maybe about a year ago, when I used to move from RxJs to Bacon, there was a problem with subscribe method so that I still avoid a use of it =) =)

[raimohanska]

Just checking: would you expect toDeferred to get the first event from the stream and ignore the rest? That's what it does as of now.

[wolfflow]

Not at all =). Ajax Stream consists only of one event value though. I think there's need for more tests e.g. using dfd.progress

[wolfflow]

And... it works as I expected=)

var D = Bacon.sequentially(100, [1,2,3]).toDeferred();
D.progress(function(x){console.log("P",x)})

P.S. For Bacon.fromArray([1,2,3]).toDeferred(), I get unsub is not defined error -- cause unsub is not defined for immediate values somehow. Will report an issue for that.

[raimohanska]

I already removed the unsub call in master. Pls have a look at https://github.com/baconjs/bacon.jquery/blob/master/src/bacon.jquery.coffee#L95

The take(1).endOnError() thing does practically the same without the problems related to manual unsub.

[wolfflow]

Yup! But there's should be progress fn call for each value in the stream to satisfy Deferred specs). What do we need to do then?

[wolfflow]

For instance, if we ditch take(1) then we'd get following behaviour:

var log = console.log.bind(console)
// async sequence values
seq = Bacon.sequentially(100, [1,2,3]).toDeferred()
seq.progress(log) // 1 - 2 - 3
seq.done(log) // 3
// 'immediate' values
immediate = Bacon.fromArray([1,2,3]).toDeferred()
immediate.progress(log) // 3 
immediate.done(log) // 3
//ajax
ajax = Bacon.$.ajax({url:"http://myurl"}).toDeferred()
ajax.progress(log) //result
ajax.done(log) //result

All except immediate.progress are OK. So, it's needed to do smth with this one and return the unsub.

[raimohanska]

Hmm.. Deferred specs? What are they and where?

[wolfflow]

nevermind, just plain jquery docs for dfd. http://api.jquery.com/category/deferred-object/
)

[wolfflow]

Look at this example -- http://codepen.io/wolfflow/pen/fcmzl/. Despite some progress event problems with fromArray, it seems to be more suitable.

[wolfflow]

baconjs/bacon.js#367