How to save the response from an asynchronous call to variable

Question

I have a API call and I expected to write response to friends variable.

getFriends = function() {
  return VK.Api.call('friends.get', {}, function(response) {
    if (response.response)
      response.response;
  });
};

var friends = getFriends();
console.log(friends)  // undefined;

In my previous question one guy told me that I can fix it with callback function and close my question. I implement a callback but again I can't get a response.

var getFriends = function(callbackFn) {
  return VK.Api.call('friends.get', {}, function(response) {
    if (response.response) {
      callbackFn(response.response);
    }
  });
};

var friends = getFriends(function(list) { return list; });

How I can write response.response to variable for a lot of next manipulations?

You **must** read the answer of the question we link to. You **can't** just return the value from your function which gets it with an asynchronous call. — Denys Séguret, May 30 '15 at 08:45
@DenysSéguret I read what I need a callback function. You **must** read the my question. I write about it in second paragraph — Bob Napkin, May 30 '15 at 08:47
you must read the whole answer, not just one sentence. There is no way to code in JavaScript without understanding this fundamental problem. — Denys Séguret, May 30 '15 at 08:51
@DenysSéguret but is it good way to close question without helpful answer? — Bob Napkin, May 30 '15 at 08:58
This question is asked many times a day. We built very complete answers like the one I linked you to so that you can read them instead of the bad incomplete ones like the one below. — Denys Séguret, May 30 '15 at 09:04

php_nub_qq · Answer 1 · 2015-05-30T08:50:55.370

-2

It's actually much simpler

var friends = null;
VK.Api.call('friends.get', {}, function(response) {
    if (response.response) {
      friends = response.response;

      console.log(friends);
    }
}

edited May 30 '15 at 08:50

answered May 30 '15 at 08:47

php_nub_qq

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Surely, you are joking, because `friends` is `null`. – Bob Napkin May 30 '15 at 08:50
@bob it will be null initially, make sure you are logging it in the callback and not the outer scope. Data will become available when the response is received. – php_nub_qq May 30 '15 at 08:50
But how I can check that the response is received? I have a lot of buttons in DOM for manipulating with response. – Bob Napkin May 30 '15 at 08:53
@bob the callback is how you check – php_nub_qq May 30 '15 at 09:58
What's up with the down-votes – php_nub_qq Jun 01 '15 at 16:57

How to save the response from an asynchronous call to variable

1 Answers1