Array

`Array.from`

Creates a new, shallow-copied Array instance from an iterable or array-like object

Syntax

JavaScript

Array.from(arrayLike, mapFn?, thisArg?)

Parameters

Parameter	Type	Description
arrayLike	Iterable \| ArrayLike	An iterable or array-like object to convert
mapFn	(element, index) => T	Map function to call on every element
thisArg	any	Value to use as this when executing mapFn

Return Value

A new Array instance

Examples

Basic Usage

const str = 'hello';
console.log(Array.from(str)); // ['h', 'e', 'l', 'l', 'o']

Practical Example

const range = Array.from({ length: 5 }, (_, i) => i + 1);
console.log(range); // [1, 2, 3, 4, 5]

Advanced Usage

const set = new Set([1, 2, 3, 2, 1]);
const arr = Array.from(set);
console.log(arr); // [1, 2, 3]

Understanding Array.from

The Array.from method in JavaScript creates a new, shallow-copied Array instance from an iterable or array-like object. It belongs to the Array object and is one of the most widely used methods for working with array values in modern JavaScript and TypeScript applications.

The method signature is Array.from(arrayLike, mapFn?, thisArg?). It accepts 3 parameters: arrayLike, mapFn, thisArg. When called, it returns a new array instance. Understanding when and how to use from() helps you write more expressive, readable code.

Common use cases for Array.from include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like array-of, array-isarray, array-fill, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for Array.from is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.