link: function ($scope, element, attrs, ngModel) {
               // if (element[0] && element[0].$touched) {
                    ngModel.$asyncValidators.smCodeUnique = function (modelValue, viewValue) {

                        if (!viewValue || _.isEmpty(modelValue.trim())) {
                            return services.Q.when(true);
                        }

                        var deferred = services.Deferred;
                        $log.info("Firing server-side validations for " + $scope.tableName + '.' + $scope.columnToTest);
                        let codeObject = {
                            id: $scope.primaryKey, tableName: $scope.tableName,
                            columnToTest: $scope.columnToTest, code: viewValue
                        };
                        return services.Http.put('api/items/checkCodeUniqueness', codeObject).then(
                            function (response) {
                                if (!response.data.isValid) {
                                    $scope.errorMessage = response.data.errorMessage;
                                    deferred.reject(response.data.errorMessage);
                                }
                                else {
                                    deferred.resolve(response.data);
                                }
                                return deferred.promise;
                            }
                        );
                    };
           //     }
            }