How is adding a lifecycle implemented in functional React components?

Question

React

I would be grateful if someone could explain on the fingers how adding a life cycle to functional components in React works. Including how the React.useEffect and React.useState hooks are implemented. It is interesting exactly what patterns are used, what is remembered where and from where it is called.
And is it worth using such functional components with a life cycle, or is it already easier to create a class: which is more profitable in terms of memory?

Answer 1

Look here https://www.netlify.com/blog/2019/03/11/deep-dive-... it's well explained here, for performance here https://medium.com/@maafaishal/react-class- compone...