# The Object isSealed() method

> Learn how the JavaScript Object.isSealed() method tells you whether an object is sealed, returning true for any object you passed through Object.seal().

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2019-04-11 | Topics: [JavaScript](https://flaviocopes.com/tags/js/) | Canonical: https://flaviocopes.com/javascript-object-issealed/

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()`](https://flaviocopes.com/javascript-object-seal/) function.

Example:

```js
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()`](https://flaviocopes.com/javascript-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).