Hacker News Reader

Comment by chenglou | Hacker News Reader

Just a reminder: the best part of React isn't about its diffing algorithm or the virtual DOM. Plenty of articles have been written on this (e.g. https://medium.com/@dan_abramov/youre-missing-the-point-of-r...). The diffing algorithm is a smart way of circumventing the fact that the DOM is so slow; there's nothing to be proud of working with such thing. Ideally your platform isn't so.

Web devs will keep reimplementing parts of React elsewhere; but at least, be inspired by some other parts of React please.

View on HN

>we can focus on examining React’s true strengths: composition, unidirectional data flow, freedom from DSLs, explicit mutation and static mental model.

So wannabe functional programming in JS ? I always wondered why Facebook didn't just go all-in on clojurescript when they did React, they have the resources to deal with any compiler/technical issues, heck they could reimplement the compiler themselves they already maintain a bunch of PHP VM/language stuff. It does everything react tries to do but better and by default.

There are a huge number of people who don't enjoy programming in lisps and don't buy the tradeoff that homoiconicity is somehow worth sacrificing all syntax for.

You can take 'good parts' from functional programming without going 'all in'. Many of us don't agree that the 'all in' is actually better.

(See Gary Bernhardt's 'Boundaries' talk [0] for an amazing explanation of what I mean by taking the good parts of FP).

React isn't really about functional programming, it's very object-oriented. And where the parent comment refers to 'composition', they mean composition of components/view code, not pure functions as you may have interpreted it as.

Personally my dive into the Clojure community has been very frustrating, I find very few answers on how to actually compose large apps, and the answers I do find basically point back to OOP (but implemented in a syntax-less, ad-hoc manner [1]).

If I've got this wrong, please tell me, I'm dying for better answers.

[0] https://www.destroyallsoftware.com/talks/boundaries

[1] Stuart Sierra - Components Just Enough Structure - https://www.youtube.com/watch?v=13cmHf_kt-Q

If you've actually seen the React wrappers in clojurescript they all look really nice primarily because homoiconicity allows you to describe DOM as clojure data (and clojure has a nice syntax for vectors/map literals which helps with readability and parsing) for eg. you have stuff like [:div {:style "width: 20px"} [:a {:href "#"} "blah"] "blah"] - that's more concise than HTML and no need to fuse HTML with JS to do it.

Also you can keep that representation as datastructures, do operations on it to transform and diff it, no need for custom objects or what not. Updates are also really nice because clojure datastructures are immutable an mutation is already isolated in to special constructs. The OO aspect of React is just a sad consequence of JS - clojure has different ways to deal with polymorphism.

My impression is that all the stuff FB guys did (React, persistent data structures, unidirectional dataflow) already exist or are more natural in clojurescript than hacking it in to JS but I'm not the authority on the subject.

Are you suggesting to throw away a decade of front-end engineering in favour of writing things in Clojure/ClojureScript? What's gonna happen next time a new language comes up in ten years? Rewrite everything?

People (at least the ones I talk/work with) do understand the value of lisp. And I myself am a defender of that Hiccup-style syntax (https://github.com/facebook/react/issues/2932) and a huge Cljs fan. But judging from this comment and previous, it seems that you underestimate the value of getting work done in an already established environment.

I'm just saying that they reinvented most of the stuff that you get from clojurescript by default, and they did it in a more awkward manner because they tacked it on top of JS.

Like they already have a JS preprocessor, have their persistent datastructures, etc. and have to deal with a lot of stuff they wouldn't need to deal with in a functional programming language.

So I'm going to try and answer your original question:

> I always wondered why Facebook didn't just go all-in on clojurescript when they did React, they have the resources to deal with any compiler/technical issues, heck they could reimplement the compiler themselves they already maintain a bunch of PHP VM/language stuff. It does everything react tries to do but better and by default.

You're not correctly estimating the resources required. Every Facebook endeavor I've heard of was an attempt to keep their millions of lines of production code unchanged with the added benefit to have new code be better. (eg. PHP->Hack, Untyped JS->Flow, DOM Manipulation->React, ...)

That said, perhaps you're not familiar with these types of codebases and aren't quite grasping the magnitude of code change that would first be required for Facebook to go "all-in on clojurescript". If you haven't had the opportunity to participate in a codebase of that magnitude, there aren't really words to describe it to you. Just know its multi man years worth of effort. In practical terms its not possible because a business also needs to iterate and release new features.

They are promoting the use of these tools to write new apps. So I'd say rewriting anything has nothing to do with it.

I couldn't have said it better.

Immediate mode UI, not functional programming, which aren't very related (most immediate mode UI systems have been done in procedural languages).

Immediate mode UI is quite similar to pull based FRP.

Just like to add, I was at the Angular 2 todo app talk last night at Google, where the Angular team unleashed a bevy of information about the internal workings and philosophy on application development. Some relevant details are that they too are embracing unidirectional flow, and the concept of immutable data. Frontend development keeps getting refined, it is very promising.

I'm not sure why that article exists given it's content can fit in a single tweet. It's 90% finger wagging "you don't know what I know" and 1 sentence of the point.

Anyways, this sentiment has become popular recently for some bizarre reason. All of the things that are the "real strengths" are in fact only possible because of virtual dom. So in my eyes the virtual dom is the important part, as the enabler.

Dan Abramov is a very knowledgeable React person, so it's not just random finger wagging. It's a shared sentiment in the React development team. Virtual DOM didn't enable React's component composition. Unidirectional data flow also has nothing to do with a virtual DOM.

Well, if it's not "random finger wagging" then that makes up for the fact that he spends several paragraphs berating the reader for not being as smart as he is and seeing what he sees and spends exactly 1 sentence explaining what it is that he sees.

Reply on news.ycombinator.com