Hooks is feature was added recently to React that I really like.

In this article, we reintroduce closures by building a tiny clone of React Hooks. This will serve two purposes – to demonstrate the effective use of closures, and to show how you can build a Hooks clone in just 29 lines of readable JS. Finally, we arrive at how Custom Hooks naturally arise.

https://www.netlify.com/blog/2019/03/11/deep-dive-how-do-react-hooks-really-work/