localStorage with angularjs and node webkit

MyCtrl.js

myApp.controller('MyCtrl', ['$scope','storageService', 

    function($scope, storageService) {
        var brain = storageService.getBrain();
        $scope.items = [];
        $.extend($scope, brain); // load from memory
        
        $scope.addItem = function(item) {
            $scope.items.push(item);
            $scope.refresh();
        };
        
        $scope.refresh = function() {
            brain.items = $scope.items;
            storageService.save(brain);
        };
    }
]);

StorageService.js

myApp.service('storageService', function () {
    var brain = localStorage.brain;
    var cache = sessionStorage.brain;

    return {
        getBrain: function () {
            brain = brain || "{}";
            return JSON.parse(brain);
        },
        getCache: function () {
            cache = cache || "{}";
            return JSON.parse(cache);
        },
        saveBrain: function (newBrain) {
            newBrain = $.extend(this.getBrain(), newBrain);
            localStorage.brain = JSON.stringify(newBrain);
        },
        saveCache: function (newCache) {
            newCache = $.extend(this.getCache(), newCache);
            sessionStorage.brain = JSON.stringify(newCache);
        }
    }
});