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
You’re looking for $.when.apply($, promises).then(function(schemas) { console.log(“DONE”, this, schemas); }, function(e) { console.log(“My ajax failed”); }); This will also work (for some value of work, it won’t fix broken ajax): $.when.apply($, promises).done(function() { … }).fail(function() { … });` You’ll want to pass $ instead of null so that this inside $.when refers to jQuery. It … Read more
The best use case I can think of is in caching AJAX responses. Here’s a modified example from Rebecca Murphey’s intro post on the topic: var cache = {}; function getData( val ){ // return either the cached value or jqXHR object wrapped Promise return $.when( cache[ val ] || $.ajax(‘/foo/’, { data: { value: … Read more
To pass an array of values to any function that normally expects them to be separate parameters, use Function.prototype.apply, so in this case you need: $.when.apply($, my_array).then( ___ ); See http://jsfiddle.net/YNGcm/21/ In ES6, you can use the … spread operator instead: $.when(…my_array).then( ___ ); In either case, since it’s unlikely that you’ll known in advance … Read more
The callbacks attached to done() will be fired when the deferred is resolved. The callbacks attached to fail() will be fired when the deferred is rejected. Prior to jQuery 1.8, then() was just syntactic sugar: promise.then( doneCallback, failCallback ) // was equivalent to promise.done( doneCallback ).fail( failCallback ) As of 1.8, then() is an alias … Read more