Checking for Object Sealing in JavaScript

Determining Object Sealing with Object.isSealed()

The Object.isSealed() method allows you to check whether an object is sealed, which means that properties cannot be added or removed, but existing properties can still have their values changed.

const car = {
    make: 'Toyota',
    model: 'Camry',
}

Object.seal(car);

console.log(Object.isSealed(car)); // true

Use Cases

Object.isSealed() is valuable when you need to confirm whether an object is sealed, restricting changes to its structure while permitting alterations to property values. For example, consider a user account object:

const userAccount = {
  username: 'jsmith',
  email: 'jsmith@example.com',
  isAdmin: false,
};

Object.seal(userAccount);

// Checking if the 'userAccount' object is sealed.
if (Object.isSealed(userAccount)) {
  console.log('The user account is sealed.');
} else {
  console.log('The user account structure can still be modified.');
}

By using Object.isSealed(), you can ensure that the object’s structure remains constant, providing data consistency within your applications.