Function return async response

Question

Like a person asked here (but his solutions as to call a nother function) https://stackoverflow.com/a/10796326/315200 ...I would like to know if its possible to have a function which doesn't call a second function on response of an async request, but simply return when the async request responses.

Something like this maybe:

function callToFacebook() {
    var fbResponse;

    FB.api('/me', function (response) {
        fbResponse = response;
    });

    return fbResponse; //Will return undefined because CallToFacebook is async
}

Isn't that possible some way, without calling another function??

What I'm trying to achieve is to have one function I can call with some parameters, which will return the response object from a async webservice, like FB.

If it was possible, this would have been given as answer instead. — Felix Kling, Jun 19 '12 at 10:24

score 2 · Answer 1 · answered Jun 19 '12 at 10:23

2

No, it's not possible.

You can't return value that is returned from async operation.

Think about it, you tell 10 people to have one mile running contest, they start now, will finish in one minute +-, but you want to know the answer now, it's not possible unless you're cheating...

answered Jun 19 '12 at 10:23

gdoron

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I just want the function to wait with the response, not guess nor cheat. – curly_brackets Jun 19 '12 at 10:41
1

@KennethB. SO the answer is it's not possible, – gdoron Jun 19 '12 at 11:23

score 2 · Accepted Answer · answered Jun 19 '12 at 10:27

In short, no. You cannot have an asynchronous function return a meaningful value synchronously, because that value does not exist at that time (as it is built asynchronously in the background).

You can, however, return a Promise object, representing the "potential return value" of the asynchronous operation, and bind a function to that object using done() or similar. That way, your function gets return semantics (instead of having to chain the control flow into a callback), and remains asynchronous.

can you give one example of this in jsfiddle plz – Manish Agrawal Jul 27 '13 at 06:34 — Manish Agrawal, Jul 27 '13 at 06:34

Function return async response

2 Answers2

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