← flaviocopes.com

The Object isSealed() method

Published Apr 11 2019

Psssst! The 2023 WEB DEVELOPMENT BOOTCAMP is starting on FEBRUARY 01, 2023! SIGNUPS ARE NOW OPEN to this 10-weeks cohort course. Learn the fundamentals, HTML, CSS, JS, Tailwind, React, Next.js and much more! ✨

Accepts an object as argument, and returns true if the object is sealed, false otherwise. Objects are sealed when they are return values of the Object.seal() function.

Example:

const dog = {}
dog.breed = 'Siberian Husky'
const myDog = Object.seal(dog)
Object.isSealed(dog) //true
Object.isSealed(myDog) //true
dog === myDog //true

In the example, both dog and myDog are sealed. The argument passed as argument to Object.seal() is mutated, and can’t be un-sealed. It’s also returned as argument, hence dog === myDog (it’s the same exact object).

I write books for developers 👇🏼