Waiting for API call to finish in Javascript before continuing

Question

something I\'ve struggled with in the past and am struggling with today is preventing an API/AJAX from continuing until you\'ve recieved your response. currently I\'m workin

Answer 1

In JavaScript, there is no concept of waiting or yielding. JavaScript continues execution, without interruption, of your code to its end. It seems weird and troublesome at first, but it has its advantages.

So the idea in scenarios such as this is that the code you wish to execute after receiving your response should be put into the callback that you give to FB.api(). You'll have to break out the code after your return statement into the response callback so that it can be executed when the response is received.

This is what you might expect from JavaScript if it were like most languages (such as C++/Java):

var futureResult = SomeAsyncCall();
futureResult.Wait(); //wait untill SomeAsyncCall has returned
var data = futureResult.GetData();
//now do stuff with data

The idea in JavaScript, however, is based around callbacks when dealing with asynchrony:

SomeAsyncCall(function(result) {
    var data = result.GetData();
    //now do stuff with data
});