trigger event after several ajax calls succeeded

Question

I wonder which is the best approach to trigger an event after several (unordered) ajax calls finished.

To make it a bit clearer, I would like to call a Method doSomethingGreat() which triggers several ajax calls, the order in which those succeed ins unnecessary. I just want to trigger an event 'SomethingGreatFinished' when all of those calls succeeded. I also don't want to chain these calls, because that would be lacking performance and would be totally against the idea of asynchronous programming.

I wonder if a.) there is a common pattern for that, b.) this can be done with the Reactive Extensions for JavaScript (RxJs) or c.) with native jquery features.

Any help is appreciated!

Answer 1

RxJS will allow you to do this using the ForkJoin operator, this operator takes N observables with a value and creates one observable that fires with an array when all N observables complete.

See Matthew Podwysocki's blog post about this operator: http://codebetter.com/blogs/matthew.podwysocki/archive/2010/04/23/introduction-to-the-reactive-extensions-for-javascript-going-parallel-with-forkjoin.aspx