AngularJS | angular.isUndefined()函数

AngularJS中的angular.isUndefined()函数用于确定isUndefined函数内部的值是否未定义。如果引用未定义，则返回true，否则返回false。

句法：

angular.isUndefined( value )

返回值：如果传递的值不确定，则返回true，否则返回false。

示例：本示例使用angular.isUndefined()函数确定isUndefined函数内部的值是否未定义。

    
        angular.isUndefined() function
          
        
        
    
   
    
        GeeksforGeeks
        angular.isUndefined()
          
        
            Date: {{date}}
                    {{isUndefined}}
            
            Date1: {{date1}}
                            {{isUndefined1}}
   
        
          
        
        
            var app = angular.module("app", []);
            app.controller('isDefinedController',
                        ['$scope', function ($scope) {
                $scope.date = new Date;
                $scope.date1;
                  
                $scope.isUndefined = angular.isUndefined($scope.date)
                        == true ? "$scope.date is Undefined." 
                        : "$scope.date is not Undefined.";
                  
                $scope.isUndefined1 = angular.isUndefined($scope.date1)
                        == true ? "$scope.date1 is Undefined." 
                        : "$scope.date1 is not Undefined.";
            }]);
        
    

输出：