Pass authentication error from factory to controller in AngularJS -

i trying implement firebase authentication via factory , pass error , authdata object controller factory. possible? can't seem figure out how. keep getting undefined variables.

if print error upon failed login console.log should expected, rest of code works. can't pass error/obj controller.

my controller:

myapp.controller('logincontroller', ['$scope', '$location', 'authentication', function($scope, $location, authentication) {  $scope.login = function() {     authentication.login($scope.user);     // error auth factory  } }]); 

my factory:

myapp.factory('authentication', ['$firebase', 'firebase_url', '$location', function($firebase, firebase_url, $location){  var ref = new firebase(firebase_url);  var authobj = {     login: function(user) {         return ref.authwithpassword({             email    : user.email,             password : user.password         }, function(error, authdata) {             if (error) {                 // pass error controller                 // i've tried following:                 // authobj.err = error;                 // return authobj.err = error;             }             else {                 // pass authdata controller             }         });     } // login   };    return authobj; }]); 

you pass error handler function factory controller. (untested):

//controller myapp.controller('logincontroller', ['$scope', '$location', 'authentication', function($scope, $location, authentication) {  $scope.login = function() {     authentication.login($scope.user, function(error, authdata) {             // access error         });  } }]);   //factory myapp.factory('authentication', ['$firebase', 'firebase_url', '$location', function($firebase, firebase_url, $location){  var ref = new firebase(firebase_url);  var authobj = {     login: function(user, errorhandler) {         return ref.authwithpassword({             email    : user.email,             password : user.password         }, errorhandler);     } // login   };    return authobj; }]);