Question

What is the purpose of destroying the functions and objects?

(a) Consume unnecessary CPU cycles

(b) Prevent the dropping of reference count to 0

(c) Centralize the responsibility to clean up

(d) All of the mentioned

I have been asked this question in an interview for internship.

This intriguing question originated from JavaScript and Memory Leak topic in portion Caching, Debugging and Animation of JavaScript

Answer 1

The correct answer is (d) All of the mentioned

Easy explanation: The primary purpose of a destroy function is to centralize the responsibility for cleaning up anything that the object has done that will:

Prevent its reference count from dropping to 0 (for example, removing problematic event listeners and callbacks and unregistering from any services).

Consume unnecessary CPU cycles, such as intervals or animations.