The Object.keys() method returns an array iterator object with the keys of an object, without changing the original object.

<!-- html element to place output -->
<p id="my_output"></p>

Example 1 – Array Object:

// variables
let cars = ['Lamborghini', 'Ferrari', 'Maserati', 'Alfa Romeo'];
let car_keys = Object.keys(cars);

// output to the HTML element
document.getElementById('my_output').innerHTML = car_keys;

Example 2 – String Object:

// variables
let car = 'Maserati';
let car_keys = Object.keys(car);

// output to the HTML element
document.getElementById('my_output').innerHTML = car_keys;

Example 1 – Array Object:

0,1,2,3

Example 2 – String Object:

0,1,2,3,4,5,6,7

Object.keys(object)

---