How to Check If Object is an Array in JavaScript

John on December 21, 2020

Sometimes one needs to check whether a variable is an object or an array in JavaScript. In this tutorial, we will learn how to do that.

Using the Array.isArray() Method

JavaScript has a built-in method for checking if something is an array called Array.isArray(). To use it pass the object to check inside the () (parenthesis) of the method.

let fruit = ['strawberry', 'orange', 'apple'];

console.log(Array.isArray(fruit));

true

Array.isArray() returns boolean true if the variable is an array and false if it is something else.

let fruit = null;

console.log(Array.isArray(fruit));

false

Here is an example of if-else logic which does something if a variable is an array.

let fruit = ['strawberry', 'orange', 'apple'];

if (Array.isArray(fruit)) {
// do something with the array.
} else {
// do something if not an array.
}

Conclusion

You now know how to check if an object is an array in JavaScript.