angularjs, service, load only once

            var events = {
                load: {
                    isPending: false,
                    error: false,
                    loaded: false
                }
            };

            this.load = function(force) {
                force = force || false;

                var dfd = $q.defer();

                var watchId = $rootScope.$watch(function() {
                    return events.load.isPending;
                },function(newVal, oldVal) {
                    if(newVal !== oldVal) {
                        if(events.load.loaded) {
                            dfd.resolve(someModel);
                        } else if(events.load.error) {
                            dfd.reject(events.load.error);
                        }
                        if(events.load.loaded || events.load.error) {
                            watchId();
                        }
                    }
                });

                if(events.load.loaded && !force) {
                    events.load.isPending = false;
                } else if(!events.load.isPending || (events.load.loaded && force)) {
                    events.load.isPending = true;
                    someResource.load(function (data) {
                        someModel = data;
                        events.load.loaded = true;
                    }, function (why) {
                        events.load.error = why;
                    }).$promise.finally(function () {
                        events.load.isPending = false;
                    });
                }

                return dfd.promise;
            };