Promise Example

promises.js

asyncCall(data,function(response){
  // You have response from your asynchronous call here.
}, function(err){
  // if the async call fails, the error callback is invoked
});

// And now with Promises pattern, you would write it like this:

var promise = asyncCall(data);

promise.done(function(response){
  // You have response from your asynchronous call here.
}).fail(function(err){
  // if the async call fails, you have the error response here.
});