JavaScript Object keys() Method

JavaScript Object.keys() method is used to return an array of a given object’s own enumerable property names.

This method is commonly used for iterating over an object’s properties.

Syntax

Object.keys(obj)

Parameters

obj(required): An iterable object.

Return Value

It returns an array of strings representing all the enumerable properties of the given object.

Visual RepresenatationVisual Representation of JavaScript Object keys() Method

Example 1: How to Use Object.keys() Method

let obj = {
 name: 'Krunal',
 education: 'IT Engineer',
 country : 'India'
} ;

console.log(Object.keys(obj));

Output

[ 'name', 'education', 'country' ]

So, in the above example, we get an array of object keys.

We can do the same with an array. We can get the array keys as well.Visual Representation of Use of array

//array 
let arr = [
 'apple',
 'microsoft',
 'amazon',
 'alphabet',
 'tencent',
];

console.log(Object.keys(arr));

Output

[ '0', '1', '2', '3', '4' ]

Example 2: Use array-like objects

let object = { 0: "Lion", 1: "Tiger", 2: "Deer" };
console.log(Object.keys(object));

//random key ordering
let object1 = {1: "Tiger", 0: "Lion", 2: "Deer" };
console.log(Object.keys(object1));

Output

[ '0', '1', '2' ]
[ '0', '1', '2' ]

Example 3: Pass the non-enumerable property

An example of a function property of an object is the Non-enumerable property. Therefore, we will not get the keys to that property.

let myObj = Object.create({}, {
  getName: {
    value: function () { return this.name; }
  }
});

myObj.name = 'krunal';

console.log(Object.keys(myObj));

Output

[ 'name' ]

Browser Compatibility

  • Chrome 5 and above
  • Edge 12 and above
  • Firefox 4 and above
  • Opera 12 and above
  • Safari 5 and above

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