jquery custom deferred functions

Question

I have three functions i\'m trying to run, the first two are doing some async stuff that need data for the third to use. I want the third function to fire only when 1 and 2 are

Answer 1

I think you should have first() and second() return a promise: return d.promise();. From the docs:

If a single argument is passed to jQuery.when and it is not a Deferred or a Promise, it will be treated as a resolved Deferred and any doneCallbacks attached will be executed immediately.

I suspect this might be why the when call is calling constructData too soon.

It's hard to tell from you code, but be sure you are calling d.resolve() after the async operations have completed.

You might find that a more natural approach to explicitly setting data1 and data2 is instead to use the data that is supplied when resolve is called. This would mean that your when call would look something like this:

$.when(first(), second()).done(function(result1, result2) {
    data1 = result1[0];
    data2 = result2[0];

    constructData();
});

Note that the exact format of results supplied to the done method depends on the nature of the deferred objects. If the promises are returned from a call to $.ajax, the results should be of the form [data, statusText, jqXhrObject].