angularjs - 別の監視対象プロパティに依存するプロパティ

Question

これらは同じように機能するようです。しかし、それらは同じですか？($scope.active に注意)

最初の1つ：

angular.module('my.controllers', []).controller('MyController', ['$scope', 'myService',
function($scope, myService) {
    $scope.myFilters = myService.myFilters;
    $scope.active = $scope.myFilters.length > 0;
    $scope.$watch(function() {
        return myService.myFilters;
    }, function(newFilters) {
        $scope.myFilters = newFilters;
        $scope.active = $scope.myFilters.length > 0;
    },true);
}]);

二つ目：

angular.module('my.controllers', []).controller('MyController', ['$scope', 'myService',
function($scope, myService) {
    $scope.myFilters = myService.myFilters;
    $scope.active = function(){return $scope.myFilters.length > 0};
    $scope.$watch(function() {
        return myService.myFilters;
    }, function(newFilters) {
        $scope.myFilters = newFilters;
    },true);
}]);