表陣列中的JavaScript對象發現

Question

我有以下對象

var columns = {ContributionType: "Employer Contribution", 
       Employee1: "0", 
       Employee2: "0", 
       Employee3: "0" 
       }; 

從這個我需要形成自己的屬性鍵數組單獨像下面

var keys=["ContributionType", "Employee1", "Employee2", "Employee3"]; 

數屬性是動態的

問題： 我該如何使用lodas h還是純JavaScript？

Answer 1

Object.keys()

var columns = {ContributionType: "Employer Contribution", 
 
       Employee1: "0", 
 
       Employee2: "0", 
 
       Employee3: "0" 
 
       }; 
 
var keys = Object.keys(columns); 
 
console.log(keys);

Answer 2

var arr=[]; 
for (var key in columns) 
{ 
//by using hasOwnProperty(key) we make sure that keys of 
//the prototype are not included if any 
if(columns.hasOwnProperty(key)) 
{ 
    arr.push(key); 
} 
}