如何使用 AngularJS 检查对象中键的存在？

给定一个包含（键，值）对的对象，任务是使用 AngularJS 检查对象中是否存在键。

方法：方法是使用in运算符来检查对象中是否存在键。在第一个示例中，输入了键“Prop_1”并且它存在于对象中。在第二个例子中，用户可以检查他们想要检查哪个键是否存在。

示例 1：

  

    
    
  
    
        var myApp = angular.module("app", []);
        myApp.controller("controller", function ($scope) {
            $scope.obj1 =
                { "Prop_1": 1, "Prop_2": 2, "Prop_3": 3 };
            $scope.res = '';
            $scope.textval = "Prop_1";
            $scope.checkK = function () {
                var txtVal = $scope.textval;
                if (!(txtVal in $scope.obj1)) {
                    $scope.res = "Key not Exists.";
                } else {
                    $scope.res = "Key Exists";
                }
            }
        });
    

  

    
        GeeksForGeeks
    
    
        Check if a key exists in 
        an object in AngularJS
    
    
        
            Object - {{obj1}}
            Enter the key: 
            
            
                Check here
            
            {{res}}
        
    

  
 

输出：

示例 2：

  

    
    
  
    
        var myApp = angular.module("app", []);
        myApp.controller("controller", function ($scope) {
            $scope.obj1 =
                { "Prop_1": 1, "Prop_2": 2, "Prop_3": 3 };
            $scope.res = '';
            $scope.textval = "";
            $scope.checkK = function () {
                var txtVal = $scope.textval;
                if (!(txtVal in $scope.obj1)) {
                    $scope.res = "Key not Exists.";
                } else {
                    $scope.res = "Key Exists";
                }
            }
        });
    

  

    
        GeeksForGeeks
    
    
        Check if a key exists in 
        an object in AngularJS
    
    
        
            Object - {{obj1}}
            Enter the key: 
            
            
                Check here
            
            {{res}}
        
    

  
   

输出：