JavaScript Array keys()

Create an Array Iterator object, containing the keys of the array:

const fruits = ["Banana", "Orange", "Apple", "Mango"];
const keys = fruits.keys();

let text = "";
for (let x of keys) {
text += x + "<br>";
}

Use the built in Object.keys() Method:

const fruits = ["Banana", "Orange", "Apple", "Mango"];
const keys = Object.keys(fruits);

let text = "";
for (let x of keys) {
text += x + "<br>";
}

Description

The keys() method returns an Array Iterator object with the keys of an array.

The keys() method does not change the original array.

array.keys()

NONE

Type	Description
An array	An Array Iterator object containing the keys of an array.

keys() is an ECMAScript6 (ES6) feature.

ES6 (JavaScript 2015) is supported in all modern browsers since June 2017:


Chrome 51	Edge 15	Firefox 54	Safari 10	Opera 38
May 2016	Apr 2017	Jun 2017	Sep 2016	Jun 2016

keys() is not supported in Internet Explorer.