Hooks aren't magic syntax. The problem with hooks has nothing to do with syntax. The problem is that the React crowd has decided to overload the meaning of a term that has had a reasonably solid interpretation (at least in comparison to the React crowd).

"React Functional Components" have nothing to do with conventional functional programming. They inherently (intentionally?) violate the spirit of functional programming through hidden global variables, while pretending that it is still functional, when in reality they should be doing the opposite. They should be upfront about the hack that hooks are. They are not functional, they are merely functions. In all other respects they operate as if the function was a method inside a class and that all hook calls are with respect to an invisible "this" keyword that contains the component's context. Since hooks are not named (which would expose their inherently pseudo-OOP nature), they associate their state through a hidden incrementing counter. It's like you're sweeping all the OOP parts under the rug to pretend to be functional so you can be a cool functional hippie too.

> They are not functional, they are merely functions.

Functional literally means dealing with functions composition.

Free of side effect is not a property of functional programming. Ocaml is functional and has side effects.

What makes it even worse is that in order to match the hidden state with the output of a render function, it has to be "reconciled" which uses usually-right heuristics to match the tree structure of the function output to the tree structure in the fiber cache.

Aren't hooks just composable effects implemented in userland? In fact, Sebastian actually asked the ECMAScript committee for effects a la OCaml 5.0 effects (https://ocaml.org/manual/5.0/effects.html) and React only built their own when the committee said "not right now", if I remember correctly.

The thing is ... you can model effects with the Free monad (or with Haskell's Backpack as was on here just the other day - https://news.ycombinator.com/item?id=45221112), so they are definitely "functional", for most variations on the definition of "functional" that I know.

Yes, that's exactly it. React is presented as functional but it's still just stateful components, except instead of OOP syntax and features making that clear, it's hidden away so that it looks functional without actually being so.

This happens because GUIs are inherently imperative constructs.

Yeah, well put tech wise (the ad personam part puts me off a bit, though). Personally I like hooks quite a lot, but e.g. I feel I have to check once a month or two if a memoized component (that’s „functional” in name) re-renders if its props stay the same and the only change is the state..