Dealing with Arrays of Deferred Objects

Question

Since using $.Deferred I\'ve run into this scenario a couple times: I have a list of values each of which yields a Deferred Object in some way and I want to execute

Answer 1

A more elegant way to write this example is with the array map function (or jQuery's $.map):

var urls = [ 'foo.com', 'bar.com', 'baz.com', 'qux.com' ];

var defers = urls.map( function( url) {
    return $.ajax({
        url: 'http://' + url
    });
});

$.when.apply(window, defers).done(function(){
    // Do Something
});

You could even roll your own "whenDone" and "fetchURL" functions:

Array.prototype.whenDone = function(callback){
    return $.when.apply(window, this).done(callback);
}

function fetchURL(url){
    return $.ajax({
        url: 'http://' + url
    });
}

var urls = [ 'foo.com', 'bar.com', 'baz.com', 'qux.com' ];    

urls.map( fetchUrl ).whenDone(function(){
    // Do Something
});