promise

promise.js

function deferredTimer(success) {
  var deferred = $q.defer();

  $timeout(function() {
    if (success) {
      deferred.resolve({ message: "This is great!" });
    } else {
      deferred.reject({ message: "Really bad" });
    }
  }, 1000);

  return deferred.promise;
}

$scope.startDeferredTimer = function(success) {
  deferredTimer(success).then(
    function(data) {
      $scope.deferredTimerResult = "Successfully finished: " +
        data.message;
    },
    function(data) {
      $scope.deferredTimerResult = "Failed: " + data.message;
    }
  );
};