$.when() will execute the failed callback (2nd parameter passed to then()) immediately if any one of the parameters fails. It’s by design. To quote the documentation: http://api.jquery.com/jQuery.when/ In the multiple-Deferreds case where one of the Deferreds is rejected, jQuery.when immediately fires the failCallbacks for its master Deferred. Note that some of the Deferreds may still … Read more
Very astute, jQuery.when is what you’re looking for. It takes either a promise or a normal non-thenable and returns a promise over that value. However, since you have functions and not values here that isn’t really required since this is the behavior of .then anyway. var queue = [syncFunction, syncFunc2, returnsPromiseAsync]; var d = $.Deferred().resolve(); … Read more
(UPDATE: Please note that currently jQuery Promises are not compatible with the Promises/A+ specification – more info in this answer.) In your function where you create the AJAX request you can also create a deferred object and return a promise to the caller after binding its resolve and reject functions to the appropriate callbacks of … Read more
The documentation update for jQuery 1.8 is not online yet. According to this recent blog post: We’re in the process of updating the API documentation for all the changes to 1.8, but for now you can refer back to the changelog in the jQuery 1.8 announcement to see what’s changed. Update: Yes, then() returns a … Read more
Am I using the wrong approach for deferreds and promises? Yes. In the asynchronous callback you should not access promises, but only the callback arguments. The return promise of $.when does resolve with an array of the .resolve() parameters for each of the promises in the array – you can loop over the arguments object … Read more
I’m a bit confused by this question. I think this is because you are confused by promise and delegate. They are in fact completely unrelated features of jQuery. I’ll explain each separately: delegate delegate is a feature of jQuery that was introduced in jQuery 1.4.2. (It is a nicer approach to the live feature that … Read more
function showData(data1, data2) { alert(data1[0].max_id); alert(data2[0].max_id); } function method1() { return $.ajax(“http://search.twitter.com/search.json”, { data: { q: ‘ashishnjain’ }, dataType: ‘jsonp’ }); } function method2() { return $.ajax(“http://search.twitter.com/search.json”, { data: { q: ‘ashishnjain’ }, dataType: ‘jsonp’ }); } $.when(method1(), method2()).then(showData); Here’s a working jsFiddle
With a custom object function DeferredAjax(opts) { this.options=opts; this.deferred=$.Deferred(); this.country=opts.country; } DeferredAjax.prototype.invoke=function() { var self=this, data={country:self.country}; console.log(“Making request for [” + self.country + “]”); return $.ajax({ type: “GET”, url: “wait.php”, data: data, dataType: “JSON”, success: function(){ console.log(“Successful request for [” + self.country + “]”); self.deferred.resolve(); } }); }; DeferredAjax.prototype.promise=function() { return this.deferred.promise(); }; var countries … Read more
Now updated for jQuery 1.8+ The easiest way to tackle this is to run the response of $.ajax through .then to filter based on success or failure of the data. $.ajax() .then(function (response) { return $.Deferred(function (deferred) { var problem = hasError(response); if (problem) { return deferred.reject(problem) } deferred.resolve(response); }).promise(); }); You could then return … Read more
Deferred Object As of jQuery 1.5, the Deferred object provides a way to register multiple callbacks into self-managed callback queues, invoke callback queues as appropriate, and relay the success or failure state of any synchronous or asynchronous function. Deferred Methods: deferred.done() Add handlers to be called when the Deferred object is resolved. deferred.fail() Add handlers … Read more