I'm sorry I can just share the link of my article here because it has a lot of pictures. I'll remove this post if the community wants me to :)

Mutation in javascript is always a very edgy topic for beginners as well as some experienced developers. In this article I try to explain how mutation in javascript works and how you can follow ways to properly work with it. Please give it a read if you want to learn about it!

https://easyontheweb.com/mutating-objects-in-javascript/