Controller/service, using the same user object for registration

Question

Sorry quite new to Angular.JS/JS/Ionic, have been working with this login controller and have the task of creating a registration controller + service any advice on approaching this in a fashion of using the information from $scope.data for a var i.e. userObj, which can be used in other controllers/services.**EDIT

Controller:

.controller('LoginCtrl', function($scope, LoginService, $ionicPopup, $state) {
  $scope.data = {};

  $scope.login = function() {
    LoginService.loginUser($scope.data.username, $scope.data.password).success(function(data) {
      $state.go('tab.dash');
    }).error(function(data) {
      var alertPopup = $ionicPopup.alert({
        title: 'Login failed!',
        template: 'Please check your credentials',
        okType: 'button-assertive', // String (default: 'button-positive'). The type of the OK button.
      });
    });
  }
})

Service:

.service('LoginService', function($q) {
    return {
      loginUser: function(uName, uPass) {
        var deferred = $q.defer();
        var promise = deferred.promise;

        if (uName == 'user' && uPass == 'secret') { <!-- some def values which are user and secret -->
          deferred.resolve('Welcome ' + uName + '!');
        } else {
          deferred.reject('Wrong credentials.');
        }
        promise.success = function(fn) {
          promise.then(fn);
          return promise;
        };
        promise.error = function(fn) {
          promise.then(null, fn);

      return promise;
        };
        return promise;
      }
    }
  })