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:


Chrome	Edge	Firefox	Safari	Opera
Yes	Yes	Yes	Yes	Yes

keys() is not supported in Internet Explorer 11 (or earlier).