javascript - 如何根据 Angularjs 中的某些条件在 Controller 中创建作用域变量

Question

我在 Angularjs Controller 中的代码如下:

$scope.validElements = [                                    
                                 {
                                    "id": "One",              
                                 }, 
                                 {
                                    "id": "Two",
                                 }, 
                                 {
                                    "id": "Three",
                                 },
                                 {
                                    "id": "Four",
                                 }
                            ];

如何使 validElements 根据条件而有所不同 ( if(someService.someElement == "ABC") ) then

$scope.validElements = [                                    
                                 {
                                    "id": "One",              
                                 },
                                 {
                                    "id": "Three",
                                 }    
                        ];

否则

$scope.validElements = [                                    
                                {
                                    "id": "One",              
                                 }, 
                                 {
                                    "id": "Two",
                                 }, 
                                 {
                                    "id": "Three",
                                 },
                                 {
                                    "id": "Four",
                                 }
                        ];

如果可能，请提供建议或任何粗略的想法如何完成

Answer 1

您似乎想创建另一个作用域变量并将其设置为等于 someService，然后在 someSome 元素上放置一个监视。然后您可以在监视函数中处理条件。我这样做是为了观察服务变量

    $scope.validElements = [ // set default here               
         {
            "id": "One",              
         } // ...
    ];
    $scope.someService = someService;
    $scope.$watch('someService.someElement', function(newValue, oldValue) {
        // or a switch statment
        if(newValue == 'ABC'){
            $scope.validElements = [                                    
                     {
                        "id": "One",              
                     },
                     {
                        "id": "Three",
                     }    
            ];
        }else{
            // handle else condition
            $scope.validElements = [                                    
                    {
                        "id": "One",              
                     }, 
                     {
                        "id": "Two",
                     }, 
                     {
                        "id": "Three",
                     },
                     {
                        "id": "Four",
                     }
            ];
        }
    });

希望这有帮助!祝你好运