Deferred callback parameters fix

[MaceWindu]

Deferred.always,Deferred.done,Deferred.progress,Deferred.fail should take callbacks as parameters.

[apare]

👍

[johnnyreilly]

Should this read "JQuery promise / deferred callbacks"?

[MaceWindu]

Yep, English is not my strong side

[johnnyreilly]

Hi @MaceWindu,

Thanks for contributing!

If I read this correctly this PR makes sure that only "then-able" style functions can be passed to the various deferred / promise methods.

On the face of it seems entirely valid. And the existing tests are passing (with a minor amend to one). That said, I'm not too close to the jQuery Promise / Deferred implementation. Does someone else on the DT team want to cast their eyes over this and merge if they're happy?

Cheers.

[MaceWindu]

Problem with previous implementation was that type parameter was declared as callback and it resulted in resolve/reject/progress/notify methods parameter to have a callback type too. This is wrong.

Now situation is better, but still not perfect. E.g. if you pass parameter of type1 to resolve(), parameter of type2 to reject(), and parameter of type3 to progress() - you will need Deferred definition with 3 type parameters (if we type only first parameter for each function, because TS doesn't support variable number of type parameters unfortunately) and you cannot have typed definition for always() - it will be type1 or type2.

[johnnyreilly]

Thanks for the clarification @MaceWindu

Would someone else on the DT team be happy to eyeball this? @vvakame @Diullei @basarat @Bartvds - any takers?

[vvakame]

@johnnyreilly I do not say anything because i do not use... sorry.

suggestion: https://github.com/borisyankov/DefinitelyTyped/blame/d89a73caaf7aa99158996a0cb1fa42fee6e2cd8d/jquery/jquery.d.ts#L300
I think that we should listen to the opinion of @AndrewGaspar.

[ryanbnl]

+1, this would fix problems on my project :)

[AndrewGaspar]

These changes seem fine to me. I'm kind of confused as to why we had the T and T[] arguments before... that seems completely wrong.

[apare]

The only isue :
var dfd = $.Deferred();
dfd.done( [ fn1, fn2 ], fn3 );

Like the documentation said : doneCallbacks is a function, or array of functions, that are called when the Deferred is resolved. Done can take function and array of function... but I don't think anyone uses array as arguments.

[johnnyreilly]

The consensus seems to be"yes" so let's merge!