prepack VS rescript

Hello HN,

I'm considering the development of a new programming language, drawing inspiration from Rust's strengths, with a focus on compiling to JavaScript. Here what I'm considering are some key features:

Strict Type System

Algebraic Data Types

*Unsafe Mode for JS/TS Interaction*: Facilitate direct interaction with existing JavaScript and TypeScript code.

No Null Usage: Option/Result patterns to avoid null.

Trait Implementation

Backend Development Priority: Initially targeting server-side applications.

Efficient Compiler Design: Including features like dead-code elimination and partial evaluation, similar to the approach of Prepack[0] (by Facebook).

I believe this approach could bring significant benefits, especially with recent advancements like Uint8Array and worker threads.

Would this be of interest to the community? Looking forward to your insights and discussion.

[0] https://github.com/facebookarchive/prepack

You can still do optimisations based purely on Javascript semantics. This is similar to the first example you give with dead function elimination, and many minifiers do some amount of this already, but you can take it to some extremes. One example of this is the (no longer maintained) Prepack project from Facebook. The core idea is to evaluate as much Javascript as possible at compile time, with the expectation that the result will probably be smaller (albeit less human readable) than the initial code.

It's no longer maintained, but I think prepack is roughly what you're looking for.

i've had code where it intentionally relied on the wrong behavior (missing hook dependencies) and when I fixed it it caused an unintentional bug (hook fired too often or sometimes infinite rerendering). Yes it is more of a bug in the code rather than React hooks issue but it is also really hard to fix/rewrite. while i'd love to jump on the hype train projects like https://github.com/facebookarchive/prepack and how concurrent mode is still experimental after five+ years doesn't give me a lot of confidence.

Some real examples in JavaScript can be seen on Prepack[2]. Consequently it is natural to wonder whether we can AOT compile components of client side frameworks, to achieve a reduction in the final bundle size, but also to increase application execution speed.

Less or more it’s likely to happen, and could have been expected 2-3 years ago.

Especially with https://github.com/facebook/prepack. They want to eventually ship pre-compiled components rather than React.createElement() to end user

https://github.com/facebook/react/issues/7324

I also think this is why facebook had been investing in `prepack` - https://github.com/facebook/prepack

While the feedback was overwhelmingly positive, I noticed that despite having TypeScript support, many developers were hesitant simply because of "ReScript" in the name. So after months of dedicated development, I'm excited to present you Sury - a TypeScript-first schema validation library that brings all those amazing features while staying true to its ReScript roots 🔥

When I see this it makes me want to run for ReasonML/ReScript/Elm/PureScript.

Sum types (without payloads on the instances they are effectively enums) should not require a evening filling ceremonial dance event to define.

https://reasonml.github.io/

https://rescript-lang.org/

https://elm-lang.org/

https://www.purescript.org/

(any I forgot?)

It's nice that TS is a strict super set of JS... But that's about the only reason TS is nice. Apart from that the "being a strict super set" hampers TS is a million and one ways.

To my JS is too broken to fix with a strict super set.

Interestingly, you probably think that calling eval itself is slow, and I thought this myself. However, it was actually not as slow as I expected. For example, creating a simple nested object schema and calling the parser once happened to be 1.8 times faster with ReScript Schema using eval than Zod. I really put a lot of effort into making it as fast as possible, and I have to thank the ReScript language and the people behind it for allowing me to write very performant and safe code.

Fortunately, the OCaml compiler is very modular, and there have been efforts to make things more... reasonable.

- Reason, a different syntactic frontend for regular OCaml: https://reasonml.github.io/

- ReScript, a language with OCaml semantics that compiles into: JS https://rescript-lang.org/ (I suppose it's a reincarnation of js-of-ocaml).

Elm, ReScript, F#, Ocaml, Scala… it’s just normal to name your types, then use them places. In fact, you’ll often create the types _before_ the code, even if you’re not really practicing DDD (Domain Driven Design). Yes, you’ll do many after the fact when doing functions, or you start testing things and decide to change your design, and make new types. Either way, it’s just “the norm”. You then do the other norms like “name your function” and “name your variables”. I’m a bit confused why it’s only 2 out of 3 (variables and functions, not types) in this TypeScript Angular project. I’ll have to look at other internal Angular projects and see if it’s common there as well.

A web application makes use of these same ingredients, i.e. HTML, CSS, and JavaScript, but it uses significantly more JavaScript. As the JavaScript powering your web application grows in size it can bring with it a variety of problems that a few languages, like TypeScript, ReScript, PureScript, and Elm, have attempted to solve. Each of the aforementioned compile to JavaScript languages have their pros and cons but it is beyond the scope of this article to get into those details. Suffice it to say, my preference is Elm. It is also not the goal of this article to convince you to use Elm but only to show you how Elm fits into the flow of creating a web application and hosting it on GitHub Pages. So let's continue by adding Elm to our project.

Since JavaScript doesn't have a pattern-matching like Rust, it could be hard to replicate the same logic. I used the ReScript compiler to maintain the original logic as much as possible. It made me able to port it confidently. Specifically check_pair function can be converted into this.