JavaScript Array isArray() Method (original) (raw)

Last Updated : 15 Jul, 2024

The**isArray()**method in JavaScript is used to determine whether a **given value is an array or not. This method returns true if the argument passed is an array else it returns false.

**Syntax:

Array.isArray(obj);

**Parameters:

**Return value:

This function returns the Boolean value true if the argument passed is an array otherwise it returns false.

**Example 1: Checking if a Value is an Array using Array.isArray()

The code defines a function func() checking if 'foobar' is an array using Array.isArray(). It logs false. 'foobar' isn’t an array, confirming the method’s accuracy.

JavaScript `

// JavaScript code for isArray() function function func() { console.log(Array.isArray('foobar')); }

func();

`

**Example 2: Passing map in isArray() Method

Since the argument passed to the function **isArray() is a map therefore this function returns **false as the answer.

JavaScript `

// JavaScript code for isArray() function function func() { console.log(Array.isArray({ foo: 123 })); } func();

`

**Example 3: Illustration of Array.isArray() Method on nested Array.

JavaScript `

// Array.isArray() method on 1D Array const arr=[1,2,3,4,5,7,6]; const result=Array.isArray(arr) console.log(result);

//Array.isArray() method on nested Array const num = [1, [4, 9, 16], 25]; const sqRoot = num.map(num => { if (Array.isArray(num)) { //to iterate over the nested array return num.map(innerNum => Math.sqrt(innerNum)); } else { return Math.sqrt(num); } });

console.log(sqRoot); // Output: [1, [2, 3, 4], 5]

`

Output

true [ 1, [ 2, 3, 4 ], 5 ]

We have a complete list of Javascript Array methods, to check those please go through this Javascript Array Complete reference article.

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