jquery-deferred

Please note This is a contrived example. function longFunc(){ var deferred = $.Deferred(); setTimeout(function(){ console.log("long func completed"); deferred.resolve("hello"); }, 3000); return deferred.promise(); } function shortAfterLongFunc(x){ console.log('short func completed with value: ' + x); return { a: x }; } processFurther(longFunc().then(shortAfterLongFunc)); // send the array for further processing Problem I am unable to figure out how to return any kind of object/function for further downstream processing after shortAfterLongFunc completes. I can console.log from

Lets say I want to process some tasks in the synchronous manner, so I have this function: function executePromiseQueueSync(queue){ var seed = $.Deferred(), finalPromise; finalPromise = _.reduce(queue, function(memo, promise){ return memo.then(function(){ return promise.funct.apply(null, promise.argmnt); }); }, seed.promise()); seed.resolve(); return finalPromise; } Now I can use it to process some files: _.each(fileList, function(element, index, list){ _.each(element, function(el, idx, lst){ promisesQueue.push({funct: processFile, argmnt:[el, index + (len - fileList.length) ,len]}); }); });

I'm writing some JS code that uses promises. For example, I open a form pop-up and I return a jQuery Deferred object. It works like this: If the user clicks OK on the form, and it validates, the Deferred resolves to an object representing the form data. If the user clicks Cancel, then the Deferred resolves to a null. What I'm trying to decide is should the Deferred instead reject, instead of resolve? More generally, I'm wondering when should I resolve to something like a null object, and when should I reject? Here's some code demonstrating the two positions: // Resolve with null. var promise =

I have been researching jquery deferred objects for a while now and I'm stumped on one thing. The "done," "always," "then," etc methods take, as their arguments, functions which should be called when the deferred object is resolved. However I tried chaining requests by passing a deferred object into the "always" method, and that seems to work too: // A is an array of data var req = ajax(url + "?d=" + A[0]).done(processResults).fail(reportFailure); for (var i = 1 ; i < A.length ; i++) { var tmp = ajax(url + "?d=" + A[i]).done(processResults).fail(reportFailure); req.always(tmp); req = tmp; }

It's a common pattern to implement timeout of some asynchronous function, using deffered/promise: // Create a Deferred and return its Promise function timeout(funct, args, time) { var dfd = new jQuery.Deferred(); // execute asynchronous code funct.apply(null, args); // When the asynchronous code is completed, resolve the Deferred: dfd.resolve('success'); setTimeout(function() { dfd.reject('sorry'); }, time); return dfd.promise(); } Now we can execute some asynchronous function called myFunc and handle timeout: // Attach a done and fail handler for the asyncEvent $.when( timeout(myFunc, [some

I have a situation where I want to cancel a deferred. The deferred is associated with an ajax call. Why I am using deferreds I don't use the normal xhr objects returned by $.ajax. I'm using jsonp, which means I can't use HTTP status codes for error handling and have to embed them in the responses. The codes are then examined and an associated deferred object is marked as resolved or rejected accordingly. I have a custom api function that does this for me. function api(options) { var url = settings('api') + options.url; var deferred = $.Deferred(function(){ this.done(options.success); this.fail

While looking for a solution similar to as described here: How to chain ajax calls using jquery I am looking for a solution using jquery v1.52. I have a set of ajax requests to be made. But each ajax request is to be sent only after completing the previous ajax call. I am trying to achieve this with jquery 1.5.2 but just unable to. Here is what I modified from the above mentioned example. It does not work. Can anyone help me get this working? Expected output is http://jsfiddle.net/k8aUj/3/ P.S: I cannot upgrade to version beyond 1.5.2 Sandy Yo! Solved! http://jsfiddle.net/sandhyasriraj/AaHZv/

Reading a JSON-Service like this: $.ajax({ url:'activeIDs', success : function(data){ // data = [14,15] var tableRows = []; for (var dataIndex=0; dataIndex < data.length; dataIndex++) { var isLast = dataIndex == (data.length - 1); $.ajax({ url: 'info?id=' + data[dataIndex], success: function(data2) { // "foo", "bar" tableRows.push(data2.name); if (isLast) { alert(tableRows.length); } } }); } } }); First network-trace is: activeIDs = [14,15] info?id=14 (takes 2 seconds) = "foo" info?id=15 (takes 4 seconds) = "bar" In this case the alert gives "2". Seconds network-trace is different: activeIDs =