Bun is now over 1M lines of Rust code.
This is approaching the size of the Rust compiler itself; except that BunJs is mostly a JavaScript interpreter wrapper + a reimplementation of the NodeJS library (Rust STD wrapper).
I think BunJS is becoming the canary for software complexity management in the LLM era.
Yeah, Cursor did the same thing, bragging about how many lines of code they managed to produce for a semi-working browser, completely missing the idea where less code is better, not the other way around.
Even if it's mostly accidental, and the code is overengineered slop (which it is), the system being able to decompose a problem and deliver something is impressive in terms of stability: it wasn't sucked into rewriting everything from scratch every time it would run into issues, it didn't have infinite subagent recursion with a one-agent-per-line type workflow, etc.
$ rg 'unsafe [{]' src/ | wc -l
10428
$ rg 'unsafe [{]' src/ -l | wc -l
736
Language Files Lines Code Comments Blanks
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Rust 1443 929213 732281 116293 80639
Zig 1298 711112 574563 59118 77431
TypeScript 2604 654684 510464 82254 61966
JavaScript 4370 364928 293211 36108 35609
C 111 305123 205875 79077 20171
C++ 586 262475 217111 19004 26360
C Header 779 100979 57715 29459 13805It also looks like the top 2 maintainers are currently actively working on getting the amount of unsafe down and it's going down quickly.
2. Turn into idiomatic rust.
At home:
> 10428
Does anyone know how exactly Bun is used by Anthropic? Is it a part of Claude Code? I'm more than slightly worried about using Bun going forward myself, but I'm not sure to what extent that applies to using Claude as well.
It seems to be used by anthropic as a way to shift the discussion window into it being acceptable that you yolomerge millions of lines.
You definitely cannot!
https://news.ycombinator.com/item?id=48073680
Didn't age well, did it?
Node.js is a distribution of the V8 JavaScript engine (the thing that executes JavaScript in the Chrome browser), along with a bunch of standard library code written mostly in C++.
Bun is a distribution of the JavaScriptCore engine (the thing that executes JavaScript in the Safari browser), along with a bunch of standard library code written mostly in Zig (and now Rust). Bun's standard library is in many cases compatible with or inspired by the Node.js standard library, but with some changes for convenience and performance.
Also at some point Bun was acquired by Anthropic. And some people feared that this will greatly influence Bun's development.
I had to literally force quit my browser because of how much it lagged iirc.
See jared comment [0]
If this helps bun and rust is a better lang for developing bun going forward with the help of claude. Then i think that is just find.
I thought rust was making the codebase complex so zig won on speed and dx.
But with llm and a large codebase it seems like rust gives fewer bug and you can develop it faster & safer.
https://news.ycombinator.com/reply?id=48133519&goto=threads%...
That said, I'm still shocked and amazed that something this big is possible these days. But as we've seen multiple times now, one of the most important things your codebase can have is a solid test suite.
I will continue to use bun, because at the end of the day, it isn't just the technology, but the talent/people behind the technology that ensures that it will be solid.
And since that hasn't changed, I will still trust bun and its direction.
Also, bun is mostly glue code and sort of "user space" libraries (my words) as Jarred has said on X, most of the underlying runtimes like JavascriptCore, etc weren't rewritten.
So this isn't like 100% of what we think of as bun was rewritten. It's more like the scaffolding and harness.
Writing software with an LLM is doing it carelessly.
It's hard for me to see this not becoming a pile of slop, but hey, maybe I'm wrong