验证不是必填字段

Question

我有三个下拉菜单来设置唯一订单值。 Html代码： -

        return {
            restrict: 'EA',
            scope: {},
            controller: function ($scope) {
                $scope.myOrder = {};
                $scope.myOrder.step = [];
            },
            link: function (scope, el, attrs) {
                scope.checked = function() {
                  if (_.uniq(scope.myOrder.step).length !== scope.myOrder.step.length) {
                     scope.notify("error", "Please set unique order value");
                   }
                 };
                scope.save = function(isValid) {
                    if (isValid) {              
                        if (!scope.values) {                                                                              
                  ApiServices.updateOrderSet(scope.myOrder).then(function (response) {
                                    scope.notify('success', response.data);
                                    scope.values = false;
                                });
                        } else {                                        
                   ApiServices.updateAddSet(scope.myOrder).then(function (response) {
                                    scope.notify('success', response.data);
                                });
                        }
                    } else {
                        scope.notify('error', 'There are errors on the form');
                    }
                };
            },

在这些下拉列表中，我应用了一个过滤器。 指令代码： -

scope.notify("error", "Please set unique order value");

我想要的是，如果用户在下拉列表中设置相同的值，即不唯一，则在保存按钮上它会通知$submitted表单也不会提交。请注意，这些不是必填字段。我也试过了if (right, true, true, true): x++; // Move towards right else if (left, true, true, true): x--; // Move towards left else: // This is where I stuck. There should be two cases where in one of them // y goes down and x doesn't change direction, in the other case x simply // flips its direction. But I wasn't able to figure it out. 但是没有用。任何人都可以告诉我该怎么做才能让它发挥作用。