← flaviocopes.com

JavaScript instanceof Operator

Published May 18 2019

The JavaScript instanceof operator returns true if the first operand is an instance of the object passed on the right, or one of its ancestors in its prototype chain.

In this example you can see that the myCar object, of class Fiesta, responds true to instanceof Fiesta, and also responds true to instanceOf Car, because Fiesta extends Car:

class Car {}
class Fiesta extends Car {}

const myCar = new Fiesta()
myCar instanceof Fiesta //true
myCar instanceof Car //true


Wanna go from noobie to expert?

I wrote an entire book on this topic 👇

I also got a super cool course 👇

© 2023 Flavio Copes Flavio Copes using Notion to Site Notion to Site

Interested in solopreneurship?