JavaScript Object.getOwnPropertyNames() Method

The Object.getOwnPropertyNames() method returns an array of all properties (except those non-enumerable properties which use symbol) found directly upon a given object.

Syntax:

Parameter:

obj: It is the object whose enumerable and non-enumerable own properties are to be returned.

Return value:

This method returns an array of string that correspond to the properties found directly upon the object.

Browser Support:

Chrome	5
Edge	Yes
Firefox	4
Opera	12

Example 1

const object1 = {
  a: 0,
  b: 1,
  c: 2,
};
console.log(Object.getOwnPropertyNames(object1));

Output:

["a", "b", "c"]

Example 2

 var obj = { 0: 'a', 1: 'b', 2: 'c' };
console.log(Object.getOwnPropertyNames(obj).sort()); // logs '0,1,2'

// Logging property names and values using Array.forEach

Object.getOwnPropertyNames(obj).forEach(function(val, idx, array) {
  console.log(val + ' -> ' + obj[val]);

});

Output:

["0", "1", "2"]
 "0 -> a"
 "1 -> b"
 "2 -> c"

Example 3

function Pasta(grain, size, shape) {
    this.grain = grain; 
    this.size = size; 
    this.shape = shape; 
}
var spaghetti = new Pasta("wheat", 2, "circle");
var names = Object.getOwnPropertyNames(spaghetti).filter(CheckKey);
document.write(names); 
 // Check whether the first character of a string is 's'. 
function CheckKey(value) {
    var firstChar = value.substr(0, 1); 
    if (firstChar.toLowerCase() == 's')
        return true; 
    else
         return false; }

Output: