Object.preventExtensions
Object.preventExtensions is a JavaScript method that prevents new properties from being added to an object, making it non-extensible while allowing existing properties to be modified or deleted. It is part of the ECMAScript 5 specification and is used to enforce immutability constraints on objects in a controlled manner. This method helps developers create more predictable and secure code by restricting dynamic property additions.
Developers should use Object.preventExtensions when they need to ensure that an object's structure remains fixed, such as in configuration objects, API responses, or when implementing certain design patterns like sealed objects. It is particularly useful in security-sensitive applications to prevent accidental or malicious property injections, and in frameworks where object shape consistency is critical for performance optimizations or validation.