Array

`Array.isArray`

Determines whether the passed value is an Array

Syntax

JavaScript

Array.isArray(value)

Parameters

Parameter	Type	Description
value	any	The value to be checked

Return Value

true if the value is an Array; otherwise, false

Examples

Basic Usage

console.log(Array.isArray([1, 2, 3])); // true
console.log(Array.isArray('hello')); // false

Practical Example

console.log(Array.isArray(new Array())); // true
console.log(Array.isArray({ length: 3 })); // false

Advanced Usage

function process(input: unknown) {
  if (Array.isArray(input)) {
    return input.map(String);
  }
  return [String(input)];
}

Understanding Array.isArray

The Array.isArray method in JavaScript determines whether the passed value is an Array. 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.isArray(value). It accepts 1 parameter: value. When called, it returns true if the value is an array; otherwise, false. Understanding when and how to use isArray() helps you write more expressive, readable code.

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

Browser support for Array.isArray 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.