`StatelessFunctionalComponent` is not something that's publicly exported, at least from `"react"`. The convention is to use the `React.FunctionComponent`, or `R

`StatelessFunctionalComponent` is not something that's publicly exported, at least from `"react"`. The convention is to use the `React.FunctionComponent`, or `React.FC` annotation. > Functions (as in the term from "functional programming") do not produce side-effects. This isn't true, even in the so-called "functional languages." Calling a function in Clojure could produce side effects, and the same is true in Haskell. In Haskell, calling a function that produces a side effect would necessarily return an IO monad, but that's a separate concern from whether the function invocation caused the side effect. > Libraries are no longer universal. You have to consider whether it's using hooks or not. You almost never have to think about this. Either a library provides hooks or it provides components. If it provides components, they could be implemented using the old component-style API or using function components; I have no idea, and it's irrelevant unless I plan to fork the library. Conversely if the library provides only a hook, I can easily wrap it in a thin component layer if that's the interface I prefer. The libraries are therefore effectively universal, since there's nothing that says I can't use a hook-based component within a function component, or vice-versa.