Rust is Eating JavaScript
Why is Rust being used to replace parts of the JavaScript web ecosystem like minification (Terser), transpilation (Babel), formatting (Prettier), bundling (webpack), linting (ESLint), and more?
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The JS tooling universe has always seemed like a Lovecraftian hellscape to me. I've managed to stay away from it so far, but if I were caught in it, of course I'd be trying to escape any way I could. It sounds like Rust's attraction here has been as a viable escape corridor rather than anything about Rust per se.
In particular, I get that everyone wants their code to be faster, and I get that certain bloaty apps (browsers) need to get their memory footprint under control, and a few niche areas (OS kernels, realtime control) can't stand GC pauses. Other than that though, what is the attraction of Rust for stuff like tooling? As opposed to a (maybe hypothetical) compiled, GC'd language with a good type system and not too much abstraction inversion (Haskell's weakness, more or less).
Has Golang fizzled? It has struck me as too primitive, but basically on the right track.
Rust seems neat from a language geek perspective, but from what I can tell, it requires considerable effort from the programmer handle a problem (manual storage reclamation) that most programs don't really have. I do want to try it sometime. So the Rust question is intended as more inquisitive/head scratching rather than argumentative.
I think once you get into rust you just have a hard time going back, and it doesn't feel "hard" anymore. I can practically rust as easily as I can python for scripting and for API servers.
Rust really only gets hard when doing library development IMO. That's when you need lifetimes and well chosen types. But that's also why Rust libraries are superb.
I had the impression Rust doesn't handle concurrency particularly well, at least no better than Python, which does it badly (i.e. with colored functions). Golang, Erlang/Elixir, and GHC (Haskell) are way better in that regard, though they each have their own unrelated issues. I had believed for a while that Purescript targeting the Erlang VM and with all the JS tooling extirpated might be the answer, but that was just a pipe dream and I don't know if it was really workable.
Rust makes multi threading very easy you can just use
undefined
thread::spawn();
But rust makes Async difficult because it's naturally stackless so you need to create your own scheduler or use someone else's like Tokio. Also, people have a bad habit of conflating async with concurrency which makes it more confusing.
Sure you can spawn threads but now you have all the hazards of shared memory and locks, giving the 2.0 version of aliasing errors and use-after-free bugs. Also, those are POSIX threads, which are quite heavyweight compared to the in-process multitasking of Golang etc. So I would say that's not really an answer.
Go routines are certainly special and hard to match, but rust has all the normal abstractions of a language like C, just with a borrow checker so you can avoid memory leaks, write after read, etc.
What exactly are the hazards of shared memory and locks? The ownership system and the borrow checker do a pretty good job at enforcing correct usage, and if you are clever you can even guarantee no deadlocks (talk at rustconf 2024 about the fuchsia network stack).
Purescript targeting the Erlang VM
Have you tried Gleam?
No I haven't, I'll take a look at it, though I felt suspicious of "task.async" as shown on the front page of gleam.run.
I don't know but I don't think rust has that problem. In fact I've always thought its data ownership paradigm is literally the most optimal approach to concurrency and parallelism. I really love using rayon in rust for instance.
True, but of course it's always a trade-off. At a certain point I have to defer to your judgment, at least until I've written some Rust code. But I've written a fair amount of C++ and a little bit of Ada and don't find them all that convenient compared to Python or Haskell or whatever. We'll see. ;)
IME a language is as good as its package manager and libraries, and cargo is great.
Go made some pretty poor design choices, and now even Google is choosing Rust for a lot of stuff instead.
Thanks, and interesting point about Wasm if that is important. You can also compile C++ to wasm but then its C++ ;). I don't know about Ada to Wasm.
I don't think Rust is quite mainstream yet either. My impression is that its type system has not caught up with Haskell's except in a few areas, but of course nobody pretends Haskell is mainstream. I haven't yet tried Idris.
Golang seems to have a decent runtime model (lightweight threads, GC) though the language itself is underpowered. There is a Golang backend for Purescript that sounded interesting to me. The thing that turned me off the most about Purescript was the JS tooling. Purescript (purescript.org) is/was a Haskell-like language that transpiles to JS, intended for use in browsers, but Typescript filled this space before Purescript got much traction. That felt unfortunate to me.
I don't think HLL (high level language) has an official definition, but informally to me it has generally meant that the language is GC'd and that the native integer type is unbounded (bignum). By that standard, Rust and Ada are low level. I've so far thought of Rust as a modernized Ada with curly braces and more control of dynamic memory reclamation. Maybe there is more going on than that. Ada is still ahead of Rust in some ways, like generic packages, but Rust is working on that.
If you have a suggestion of a no-nonsense Rust book, I'd be interested in looking at it. https://doc.rust-lang.org/book/ beat around the bush way too long before discussing the language, but I guess I should spend more time with it.
I'd say Rust is definitely mainstream. Obviously not the level of JS or Python, but it's being used all over the place. All FAANG companies, the Linux kernel, JS runtimes, web browsers, Android, Signal, Mullvad...
IMO GC has nothing to do with high or low level. It's just incidental that there's a correlation. In GC you usually don't need to think about manually allocating or deallocating memory or truly understand what pointers are (in some ways anyway). In C / C++ you do.
In Rust you almost never manually allocate or deallocate, and you have both very high and low level APIs.
I'd say Rust is both high and low level. It just depends what you use it for. If you want to build a CLI or a web server, it's great for that. If you want to do kernel stuff and choose to flip bits around you can do that too.
As for books, maybe you'd like trying Rustlings instead.
rust is both high and low level
I like to describe this as "low level language with high level ergonomics"
Thanks, Rustlings doesn't sound like what I want either. I was hoping for a counterpart of Stroustrup's C++ Reference Manual, or Riehle's "Ada Distilled" or even K&R's book on C. Something that systematically describes the language rather than distractions like the toolchain, mini projects, cutesey analogies, etc. I'm being too persnickity though, mostly because it hasn't been important to me so far.
Sounds like you want the Rust Book: https://doc.rust-lang.org/book/
Edit: Just realized you said you didn't like it sorry
I'll probably have to read through it or maybe the Ferrocene standard, but for now, Comprehensive Rust is pretty good. I've been busy today but hope to finish it soon. Is it really true as someone mentioned that Rust binaries are always statically linked? That has its attractions but I would hope it's controllable. Can you use the regular linker (ld) with it?
Rust libraries are statically linked by default yes, except for a couple of rather low level ones (glibc and a couple others I think) - Honestly though I'd be surprised if you come across a situation where it's something necessary to think about in practice
I usually pick Rust for CLI tools because:
- It's statically compiled and isn't dependent on system binaries and won't break if there if the system has the wrong version like C/C++, allowing you to distribute it as a single binary without any other installation steps
You can do that with C++ too.
- Still produces fairly small binaries unlike languages like Java or C# (because of the VM)
I mean, the jars are actually pretty small; but also I really don't get the storage argument. I mean we live in a world where people happily download a 600 MB discord client.
- Is a modern language with a good build system (It's like night and day compared to CMake)
Meson exists ... as do others.
- And I just like how the language works (errors as values etc.)
Fair enough; though why? What's wrong with exceptions?
I work in a code base where I can't use exceptions because certain customers can't use exceptions, and I regularly wish I could because errors as values is so tedious.
- Is a modern language with a good build system (It's like night and day compared to CMake)
Meson exists ... as do others.
But they are not the default option. And your new job may not use them.
- And I just like how the language works (errors as values etc.)
Fair enough; though why? What's wrong with exceptions?
Exceptions is a non standard exit point. And by "non standard" I'm not talking about the language but about its surprise appearance not specified in the prototype. Calling double foo(); you don't know if you should try/catch it, against which exceptions, is it an internal function that may throw 10 level deep ?
By contrast fn foo() -> Result<f64, Error> in rRst tell you the function may fail. You can inspect the error type if you want to handle it. But the true power of Result in Rust (and Option) is that you have a lot of ergonomic ways to handle the bad case and you are forced to plan for it so you cannot use a bad value thinking it's good:
foo().unwrap() panic in case of error (see also expect) foo().unwrap_or_default() to ignore the error and continue the happy path with 0.0 foo().unwrap_or(13.37) to use your default foo()? to return with the error and let the parent handle it, maybe That sounds a lot like how checked exceptions work, though with some terser handling syntax.
First time I hear about checked exceptions. How do you use them ? Are you forced to handle them explicitly ? Is the handling checked at compile time ?
Checked exceptions require a function to declare the exceptions it can throw. The caller function must then catch and handle the exception, or the exception would bubble up a level, in which case the caller must also include that exception among the exceptions it declares that it can throw. I don't know if C++ does this, but Java/C# do. It sounds exactly like Rust's system except with different syntax.
But they are not the default option. And your new job may not use them.
Who cares if it's the default? If it's the best tool, use it.
It's silly to have a reason for "going Rust" be the build system, especially in the context of something as new as a WASM context where basically any project is going to be green field or green field adjacent.
Exceptions is a non standard exit point. And by "non standard" I'm not talking about the language but about its surprise appearance not specified in the prototype. Calling double foo(); you don't know if you should try/catch it, against which exceptions, is it an internal function that may throw 10 level deep ?
And that's a feature not a bug; it gets incredibly tedious to unwrap or forward manually at every level.
By contrast fn foo() -> Result<f64, Error> in rRst tell you the function may fail. You can inspect the error type if you want to handle it. But the true power of Result in Rust (and Option) is that you have a lot of ergonomic ways to handle the bad case and you are forced to plan for it so you cannot use a bad value thinking it's good:
You can do this in C++ https://en.cppreference.com/w/cpp/utility/expected (and as I said, if you feel so inclined, turn off exceptions entirely); it's just not the "usual" way of doing things.
Maybe give it a try; it's my favorite language to write programs in now, it has an extremely good standard library, and for everything else there's a mass of high quality crates, its build system is actually competent and makes compiling on Windows or Linux trivial, plus many, many more quality of life features.
If Rust had been around when I was an underclassman, I would have been totally locked into the full CompSci track. Instead, I got introduced to Java and C (and calculus…) and that looked like a nightmare compared to what I had been playing with in JS/Python land, so I noped on out of there and got a Comp Sci Lite degree.
Years later, I’m just completely in love with Rust.
I'm currently an underclassman and my OS class has a few assignments that let you choose to use c or rust. You convinced me to try rust
Hell yes! That was the point of my rambling though I never quite got there. I was wondering if curriculums had caught up yet, to at least look at the modern system languages. Sounds like you’re at a good program.
Yes it's on my infinite todo list. I'm just being too much of a curmudgeon about the available textbooks, and had a sinking feeling when the main one didn't get "hello world" out of the way on page 1, and shift to the specifics of the language.
Rust By Example is very good for showing the ropes in a very practical way, that's how I got up and running with it.
Secondly is the O’Reilly book Programming Rust, which is probably closer to what you want, it explains the actual technical details of much of the language, and to me seems written for an audience that already knows programming. Lastly would be Rust for Rustaceans by No Starch Press, if you actually do want to pursue Rust further, as it discusses very, very in detail the systems of the language, and how they can be used to make something so powerful like Serde.
Thanks, Rust by Example looks ok, and I'm acquainted with one of Programming Rust's authors, which is cool. I'm currently looking at "Comprehensive Rust". All these though seem to be about the Rust software ecosystem (compilers, package tools, libraries) as much as they are about the language. I had hoped to start by just reading about the language, if something like that exists. I don't particularly want to write any Rust programs until I've finished reading some kind of language overview, which means that all the stuff about build tools are just a distraction during that stage. As another commenter in this thread said though, ecosystems and languages have become pretty much inseparable, so maybe that's why the books are that way.
This also looks interesting:
https://dr-knz.net/rust-for-functional-programmers.html
This says nothing about Rust, but it's a humorous classic. I'd be interested to know how to describe Rust in these terms.
https://james-iry.blogspot.com/2009/05/brief-incomplete-and-mostly-wrong.html
I’ve used it the last few years to do Advent of Code (https://adventofcode.com/) and that’s been fun and challenging. Definitely recommend it. Better than trolling through a book of “now do this” examples if you’ve done other languages in the past.
I know that the "project" approach to learning a language works for some people, but I've found l greatly prefer to read a book from beginning to end before undertaking any projects. It helps me start out with a clear picture. I'm finding "Comprehensive Rust" to be fairly good so far. Thanks for all the help, everyone.
Thanks, I was looking for a more straightforward academic-style textbook for non-beginning programmers, but I'll make do with what is out there.
This is what I've been going through, sold as teaching rust to people who already know other languages. I'm not very far in at all, but it seems decent? https://google.github.io/comprehensive-rust/
Has Golang fizzled? It has struck me as too primitive, but basically on the right track.
My biggest issue with Golang by far is the close tie to Google. They are not our friendly innovator, time and time again they make decisions that will help them earn more ad money, and nothing else. And they have a lobg history of releasing something and then never fix the issues with it, and then more or less abandon it.
Other than that there are afaik some other issues with go, I'm not an expert but from what I hear the GC is quite aggressive and you can't tell it to run when you want. Doing something time sensitive? Well, bad luck. GC time!
the close tie to Google.
Guess who's one of the rounders of the Rust Foundation...
True about Google ;). Yes, there are programs that really don't want GC. I consider those to mostly be niche applications since most of us are fine with using e.g. Python, which has automatic storage management (won't quibble about whether it is GC per se) that has occasional pauses. SImilarly, tons of important programs are written in Java, which is GC'd. Of course Java is tied up with Oracle just like Go is tied up with Google.
Go's main problem from what I can tell is that the language itself is too old fashioned. I've used it but am not expert. It feels like an improved version of C, rather than a modern, type-safe language.
The GC in Go is fantastic IMO since it runs in a separate thread. I used it since 1.0 (switched our product from node.js), and dealt with all the the pain of an imprecise GC (fixed in 1.5?) and all the little improvements to arrive at it's current state.
The main issues I have with it are pretty core to the language, unfortunately, such as:
interface{} is basically a void*, but since it's a fat pointer, it can hold nil without itself being nil, which can happen by accident defer just isn't good enough Maybe they fixed some of those issues, idk, I haven't used it for several years. I did use it for about 10 years though.
Not sure if that's what you are referring to as destructors, but they added a new way to have code run at resource collection in go 1.24
I assume you're talking about runtime.
AddCleanup()? That's certainly nice, but it's not the same as a destructor since it only runs at GC time. It's useful for cleaning up data used by a shared library or something (e.g. something malloc'd by a C lib), but it only solves part of the problem.
I'm talking about scope guards. In Rust, here's how you deal with mutexes:
undefined
{
let value = mutex.Lock();
... use value ...
// mutex.Unlock() automatically called
}
The closest thing in Go is defer():
undefined
mutex.Lock() defer mutex.Unlock()
That works most of the time, but it doesn't handle more complex use cases, like selectively unlocking a mutex early while still guaranteeing it eventually gets unlocked.
Rust fixes this with the Drop trait, so basically I can drop something early conditionally, but it'll get dropped automatically when going out of scope. For example:
undefined
struct A(String);
impl Drop for A {
fn drop(&mut self) {
println!("dropping {}", self.0)
}
}
fn main() {
let a = A("a".into());
let b = A("b".into());
let c = A("c".into());
drop(b);
}
Without the last line, this prints c, b, a, i.e. stack order. With the last line, it instead prints b, c, a, because I drop b early.
This is incredibly useful when dealing with complex logic, especially with mutexes, because it allows you to cleanly and correctly handle edge cases. Things are dropped at block scope too, giving even more control of semantically releasing things like locks.
That said, 1.24 added WASM, which is really cool, so thanks for encouraging me to look at the release notes.
Thanks for taking the time to explain it. Indeed the new runtime method does not guarantee when the resource will be cleaned, so something like that Drop trait would be quite useful
Go is fine, but it has its flaws. I prefer Rust because:
() is semantically different), so no surprises with contracts It takes longer to learn, but I'm about as productive with both now.
Thanks, "Comprehensive Rust" is readable so far, though I haven't gotten to the "fun" (memory management) parts yet.
The JS tooling universe has always seemed like a Lovecraftian hellscape to me.
That's most of any programming of today for me.
If it can't be grasped in a couple of days - then na-ah.
I can patch something I need working which doesn't, written in C.
autotools ftw
I think there's room for a rust-lite language that is GCed. Something with a functional-style type system and that compiles to machine code.
Roc is a candidate for this language. Basically Elm that compiles to machine code, but with a number of tweaks to make it work for more than just a web front end. Like Elm, the type system is haskell like, but simplified.
There’s already Swift, which isn’t garbage collected, but the ref. counting does the same in practice.
The only problem with Rust and Swift, Kotlin etc. in my opinion is that they keep growing and getting more complex with no signs of stopping.
Thanks, Roc sounds interesting. Ocaml also maps more closely to machine operations than Haskell does, so it has always seemed like another alternative. AMD has something called ROCm which is their version of CUDA, but I assume that is unrelated.
Sounds kinda like Go. It's not functional, but functional patterns work well there.
It's not great for FE though.
What's FE?
Front end