Comment by ojkelly | Hacker News Reader

Comment by ojkelly | Hacker News Reader

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Most of the ideas at play here come from the functional programming world, which is why it’s often viewed from that lense.

React builds on functional reactive programming, something the FP world is known for[0]. I’m not saying it’s pure FP in the dogmatic sense, I just wanted to point out it’s closer to FP than the other paradigms.

Without the ability to interact with the outside world (side-effects), FP is not of much practical use. Not to say it’s bad or shouldn’t exist, just we need to add to it a bit to make it useful.

Why would we do that? Because the underlying ideas and principles provide a great foundation. Building on that to get FRP and algebraic effects, monads and so on, is very different to starting from OOP and brining FP ideas over.

React hooks are an interesting and tricky thing to put in a box, because they’re almost monads, almost thunks, almost algebraic effects. The interplay with fibers and components makes them hard to pin down, but they are much closer to functional than any other paradigm.

[0] https://wiki.haskell.org/Functional_Reactive_Programming

The web is (was) a pretty good example of something akin to FP: REST means all state is transferred with the response and then the whole thing is rendered in the browser. And then there is HTTP, so if you want a new page, you simple call another URL (like a function call). OK this is glossing over some parts like that cookies are also send, but they are additional optional arguments of that request (function call). That's what the mean (or meant, since the term is now muddied), when they say the connection is stateless.

What we have with badly written React apps now (90% approx.) is a UI, that is not at all behaving like a typical website and very far from being like FP. We often cannot simply go back with the back button and expect to see the same page rendered. I mean we can, but the websites will fart in our face, if we do. We do not get the ability to simple send a link to someone and have them see the exact same page. It is a huge departure from anything FP.

Furthermore from the dev perspective components feel more mainstream OOP than FP, since they store internal state and update it, which indirectly causes things I described above.

Not sure where people see the FP. Not sure they really have done any FP language before or tried in projects to strictly adhere to FP principles, because that looks a lot differently than React components and mixing state, layout and styling in JSX/TSX.

> React hooks are an interesting and tricky thing to put in a box, because they’re almost monads, almost thunks, almost algebraic effects. The interplay with fibers and components makes them hard to pin down, but they are much closer to functional than any other paradigm.

They're almost classes (/objects). The implementation is what it'd look like if you wanted to make a weird half-assed OO... thing. Property and method declarations, getting attached (ultimately) to an object. But it's FIFO access/calling, rather than using named properties and methods w/ a lookup step. And the declaration syntax is bizarre and hard to read. And they're slower than regular JS OO (because they add an extra layer of JS on top of it).

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