JavaScript (ES2026) reference · Array Methods

JavaScript Array.from() Method

Create a new array from an iterable or array-like object, with an optional function to map each element.

JavaScript (ES2026) Since ES2015

Syntax

Array.from(items, mapFn, thisArg)

Parameter	Description
`items`	An iterable (string, Set, Map, …) or array-like object (has `length`).
`mapFn` optional	Called on each element.

A new array.

From strings and setsTry it yourself

console.log(Array.from("hey"));
console.log(Array.from(new Set([1, 1, 2])));

Output

[ 'h', 'e', 'y' ]
[ 1, 2 ]

Build a rangeTry it yourself

console.log(Array.from({ length: 5 }, (_, i) => i * i));

Output

[ 0, 1, 4, 9, 16 ]

From a MapTry it yourself

const map = new Map([["a", 1], ["b", 2]]);
console.log(Array.from(map), Array.from(map.keys()));

Output

[ [ 'a', 1 ], [ 'b', 2 ] ] [ 'a', 'b' ]

Version	Change
JavaScript ES2015	Added

Array.of() · Create a new array from its arguments. Unlike Array(3), Array.of(3) makes [3], not an empty array of length 3.
Array.isArray() · Return true if a value is an array. More reliable than typeof, which reports 'object' for arrays.
JavaScript Arrays · tutorial
JavaScript Array Methods · tutorial