Angular - Promise $q

gistfile1.js

function asyncGreet(name) {
      var deferred = $q.defer();
 
      setTimeout(function() {
        // since this fn executes async in a future turn of the event loop, we need to wrap
        // our code into an $apply call so that the model changes are properly observed.
        scope.$apply(function() {
          if (okToGreet(name)) {
            deferred.resolve('Hello, ' + name + '!');
          } else {
            deferred.reject('Greeting ' + name + ' is not allowed.');
          }
        });
      }, 1000);
 
      return deferred.promise;
    }
 
    var promise = asyncGreet('Robin Hood');
    promise.then(function(greeting) {
      alert('Success: ' + greeting);
    }, function(reason) {
      alert('Failed: ' + reason);
    });