Join 2 'threads' in javascript

Question

If I have an ajax call off fetching (with a callback) and then some other code running in the meantime. How can I have a third function that will be called when both of the

Answer 1

You can do this easily with Google's Closure library, specifically goog.async.Deferred:

// Deferred is a container for an incomplete computation.
var ajaxFinished = goog.async.Deferred();

// ajaxCall is the asynchronous function we're calling.
ajaxCall( //args...,
    function() {  // callback
      // Process the results... 
      ajaxFinished.callback();  // Signal completion 
    }
);

// Do other stuff...

// Wait for the callback completion before proceeding
goog.async.when(ajaxFinished, function() {
    // Do the rest of the stuff...
});

You can join multiple asynchronous computations using awaitDeferred, chainDeferred, or goog.async.DeferredList.