Javascript — How to check if a variable is an Array?

In JavaScript, we can check if a variable is an array by using 3 methods.

1. isArray method
2. instanceof operator
3. checking the constructor type if it matches an Array object

Method 1: isArray Method

Checks whether the passed variable is an Array object.

Syntax:

Array.isArray(variableName)

Method 2: instanceof operator

Used to test whether the prototype property of a constructor appears anywhere in the prototype chain of an object.

Used to evaluate if the given variable has a prototype of ‘Array’.

Syntax:

variable instanceof Array

Method 3: Checking the constructor property of the variable

Checks its constructor with Array.

Syntax:

variable.constructor === Array