1.7 KiB
1.7 KiB
title
| title |
|---|
| Object Freeze |
Object Freeze
The Object.freeze() method freezes an object. A frozen object will prevent you from:
- Adding new properties to it
- Removing existing proprerties from it
- Changing the enumerability, configurability, or writeability of it's existing properties
Syntax
Object.freeze(obj)
Parameters
obj
- The object to freeze.
Returns
The frozen object.
Important Note
Attempting to add, remove, or modify properties of a frozen object will result in a failure. This failure will either be silent or a thrown TypeError (if Strict Mode is enabled). Additionally, Object.freeze() is a shallow operation. This means that nested object, of a frozen object, are modifiable.
Example
// Create your object
let person = {
name: 'Johnny',
age: 23,
guild: 'Army of Darkness',
hobbies: ['music', 'gaming', 'rock climbing']
}
// Modify your object
person.name = 'John'
person.age = 24
person.hobbies.splice(1,1)
delete person.guild
// Verify your object has been modified
console.log(person) // { name: 'John', age: 24, hobbies: ['music', 'rock climbing']
// Freeze your object
Object.freeze(person)
// Verify that your object can no longer be modified
person.name = 'Johnny' // fails silently
person.age = 23 // fails silently
console.log(person) // { name: 'John', age: 24, hobbies: ['music', 'rock climbing']
// The freeze is "shallow" and nested objects (including arrays) can still be modified
person.hobbies.push('basketball')
consol.log(person.hobbies) // ['music', 'rock climbing', 'basketball']