fcall/fapply difficulties

[Kiran Sonnad]

Having trouble understanding exactly how to use fcall and fapply in this situation:

1  return promiseReturningFunction()

2  .then(anotherPromiseReturningFunction)

3  .then(function() { return promiseReturningFunctionWithArgs(arg1, arg2); })

4  .then(doSomeStuffFunction)

5  .fail(doFailureStuffFunction);

For brevity and clarity, I'd like to transform line 3 into

3  .fcall(promiseReturningFunctionWithArgs, arg1, arg2)

or

3.  fapply(promiseReturningFunctionWithArgs, [arg1, arg2])

But changing that line causes TypeError failures.  Am I misusing these?

[Kris Kowal]

Yes, fcall and fapply are for calling function a promise resolves to, or in the common case, for calling a function such that the result is guaranteed to be a wrapped in a promise.

Examples:

Q.fcall(function () {
});

Q(function (one, two, three) {
}).fcall(1, 2, 3);

We do not have an abbreviated form for your line 3.

Kris Kowal

[Kiran Sonnad]

Okay. Thanks for the speedy response.