Shawn Wang (@swyx) wrote about how React hooks work internally. The article is a deep dive into JavaScript closures, and builds up to a 28-line React clone with support for the useEffect and useState hooks.

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.

Understanding how React deals with hooks internally isn't a required to use them, but it's interesting material nonetheless!

You can read the full article on the Netlify blog.