freezingObjects.js

const user = {
  firstName: 'Akash'
}

// Freezing Object
Object.freeze(user)

console.log(Object.isFrozen(user)) // true
console.log(Object.isSealed(user)) // true
console.log(Object.isExtensible(user)) // false

// Try to update content
user.lastName = 'Rajvanshi'
console.log('lastName' in user) // false

delete user.firstName
console.log('firstName' in user) // true

user.firstName = 'Abha'
console.log(user.firstName) // Akash

const descriptor = Object.getOwnPropertyDescriptor(user, 'firstName')
console.log(descriptor) // { value: 'Akash', writable: false, enumerable: true, configurable: false }