JavaScript : Checking whether a variable is an array

JavaScript arrays are fundamental data structures used extensively in web development. Ensuring the integrity of array data is essential, and the isArray() method provides a convenient solution for verifying whether a variable is an array. In this article, we’ll explore the functionality of isArray(), its syntax, and practical applications with detailed examples.

Understanding isArray()

The isArray() method in JavaScript checks whether a variable is an array and returns true if it is, and false otherwise. It offers a reliable way to perform array type checking, ensuring code reliability and integrity.

Syntax

The syntax for isArray() is straightforward:

Array.isArray(value);

const arr = [1, 2, 3, 4];
console.log(Array.isArray(arr));
// Output: true
const str = 'hello';
console.log(Array.isArray(str));
// Output: false

const obj = { 0: 'a', 1: 'b', length: 2 };
console.log(Array.isArray(obj));
// Output: false
const arr = Array.from(obj);
console.log(Array.isArray(arr));
// Output: true

console.log(Array.isArray(null));
// Output: false
console.log(Array.isArray(undefined));
// Output: false