Perry Compiles TypeScript directly to executables using SWC and LLVM

8 hours ago (perryts.com)

I understand that implementing the TypeScript compiler is not the same thing as implementing all Node.js APIs, but still, advertising "no runtime" and then requiring JS runtime (and a full local Rust setup to compile it) for something as basic as an Express web server makes the "no runtime" claim look like a slight exaggeration. I'm not saying that it's bad, it's just that the website is too optimistic.

Edit: as discussed in the thread below, the most likely reason for that is that Express is pure JS with types from @types/express, so the TypeScript compiler bails on it. Reasonable, but still frustrating.

Overall, it seems like every time I decide to try a vibe coded compiler I get this feeling like when you see a plate with fruits on a table but, coming closer, see that they are fake plastic fruits. No, I cannot use it to build a native binary of my project without V8 as easy as shown on the front page. Maybe some other project, yes, but not a real one.

Unrelated: if a project is called Perry, should the icon be a platypus in a hat, you know?

  • This seems either wrong or very uncharitable.

    > Perry exposes a faithful subset of Node.js’s stdlib HTTP server modules on top of hyper + rustls + tokio-tungstenite. The whole shape — handler signature, IncomingMessage / ServerResponse properties + methods, TLS opts, ALPN-negotiated HTTP/2, WebSocket upgrade dispatch — works unmodified, so unmodified Node servers (Express / Koa / Polka / hono via @hono/node-server / etc.) compile and run natively[1]

    It's pretty standard for "no runtime" to mean nothing on the device you install the compiled target app.

    I think iOS development still needs Ruby for Pod installation but no one says Swift apps need a Ruby runtime for example.

    [1] https://docs.perryts.com/stdlib/http.html

    • Well, I did indeed spend some time playing with it before writing my comment. I first tried to compile the TypeScript project I'm working on, and it happens to be an Express server. After some minor unrelated fixes required (Perry does not understand importing "fs/promises", so I fixed it to import "fs" and then taking .promises) it said it needs JS runtime, and the smallest repro I found was

        $ cat index.ts
        import * as express from 'express';
        const app = express();
      

      which gives

        $ perry index.ts
        Collecting modules...
          JS module: express -> /private/tmp/ex/node_modules/express/index.js
        Error: build pulled in `perry-jsruntime` (QuickJS-based eval-equivalent runtime)   via the following file(s):
          - /private/tmp/ex/node_modules/express/index.js [express]
        
        `perry-jsruntime` is treated as a privileged dependency on par with adding a JIT to the binary — it re-introduces arbitrary runtime code execution and defeats Perry's structural advantage over Node. Refusing to link by default. (#499)
        
        To enable, set `perry.allowJsRuntime: true` in the host package.json, or pass `--enable-js-runtime` on the CLI for a one-off build. (Falls under `--lockdown` deny set when that flag ships — see #496.)
      

      Maybe it's because Express is written in JavaScript with external types from @types/express, that would explain why it might need JS runtime, but it does not make things easier for me.

      2 replies →

    • > It's pretty standard for "no runtime" to mean nothing on the device you install the compiled target app.

      Only by layman that don't understand compilers.

      3 replies →

  • I am taking this attitude to an extreme with tsz. I don't want to announce to the world that tsz is ready until I tested it really really well.

    Currently tsz passes nearly 100% of TypeScript tests but that is not enough. I want it to be able to type check complex things like type-challenges solutions or complex utility type packages. I'm stress testing it with a repo with 1.5 million lines of code.

    I'm constantly assigning AI agents tasks to find bugs in tsz and open issues.

    I'll say this is "alpha" when it can do all those things plus matching tsc exactly in thousands of open source projects where tsc reported type errors. It's easy to find CI runs that tsc reported errors. I'll build a database of all the cases I've verified tsz with and will publish those. Hoping that can give folks confidence that tsz is robust

    For now, tsz is just a work in progress.

    https://tsz.dev

  • To be fair, nowhere on the frontpage does it say it can build libraries that depend on node. It seems like you are just waiting in the bushes to dis AI assisted coding.

First of all, congrats.

The website doesn't explain how it works in a lot of detail. I am the author of tsonic [1], a TS compiler that produces binaries via Clr NativeAOT (on Linux/Mac). The hardest parts were numbers (TS has no ints or shorts), Generics, and TS Utility Types. I've been on it for the last 6 months (almost every day); getting to near complete TS compatibility is a very long journey because of its expressiveness.

Add: A request is to explain how it works on the website. I did take a look at https://www.perryts.com/en/internals/ but are those techniques described really sufficient to express TS? Based on my experience, I must say I'm surprised. But the proof is in the pudding, and if it's compiling those examples it must be working somehow!

[1]: https://tsonic.org

  • Hey there, I'm going to check out your project because the comments here have me a little worried that OP's project might have some quality issues.

    Two things I found a little confusing from the docs though:

    I couldn't easily find a page describing what it can't do yet. I saw that it only works with a "strict, deterministic subset of TypeScript", but is there a page showing what's included and not included in that subset?

    Also, what's an "ambient surface" in this context? Is that a compiler term I'm just not familiar with?

    • > strict, deterministic subset of TypeScript

      I'll add that page, thanks. Today, almost all of idiomatic TS is supported including most of its utility classes. Dynamic JS-style code is not supported, for example adding a function or a field into an object, prototype-based class modifications etc. I'll compile a list, and include it along with the large docs cleanup planned before v1.

      > Also, what's an "ambient surface" in this context?

      The idea is that when JS gets transpiled into C# (or Rust, upcoming), JS globals and built-ins are invalid. The native "surface" is C#, meaning the string is .Net's string type and the methods that you expect on JS strings would be missing. But when you opt in to a surface, such as the "JS surface", the compiler applies surface defined translations such as substring becoming SubString, either directly or via a companion helper class. This allows you to write against standard JS and Node APIs, instead of relying on the stdlib/builtins of the target framework (currently CLR). And you get the JS "stdlib" - console, JSON, Date, Map, Set etc.

      For example, all the projects you see under this use the JS surface: https://github.com/tsoniclang/proof-is-in-the-pudding/tree/m...

      1 reply →

  • > The hardest parts were numbers (TS has no ints or shorts)

    The easy way to handle that would be to just treat "number" as 64-bit float, since that is semantically how Javascript defines them. But that can hurt performance.

    Another option is to define your own integer types

    • > Another option is to define your own integer types

      This is what I did. Most int usage is inferred, but if they had to define it explicitly, I make them import { int } from "@tsonic/core/types.js";

Fascinating. I've written cross platform (WASM, iOS, Android) libraries with Rust before and had a good time but Rust can be a pain too. Cross-platform Typescript is a really interesting proposition.

That said, the more I think about it the more dubious I am. The site boasts no runtime dependencies but clearly it’s going to need things like a garbage collector, you can’t just magic that requirement away. At a certain point is it just doing what a JS engine’s JIT compilation does… except ahead of time?

Also doesn't inspire confidence that the text on the site is very clearly AI generated and the GitHub log shows an endless stream of AI powered commits. About 15 per hour, every hour? Doesn’t scream stability.

  • how do one tell when text is ai generated - honest question. What are the tell tale signs?

    • vibrant colours that don't match

      X. Y. SUPER Z. heading

      X. Y. SUPER Z. in subheading

      excessive purple and gradients

      --> arrows

      cards, cards, cards, cards

      doesn't just X, emdash, it [SUPER Y]

      more cards

      ridiculous awful contrast in copy that makes things unreadable (grey on black etc)

    • In regards to the site, all of them follow almost the same templates.

      Once you see a few, it becomes obvious

Why are all vibe-coded web-site cards so stupidly identical ? I have seen dozens of these and whenever they use cards, there is an icon taking valuable space by itself followed by a header. That is ridiculous design and any designer/CSS developer would point that out. So why do LLMs emit this ?

Perry uses NaN-boxing to preserve TypeScript's dynamic type system at runtime, the same approach as JavaScriptCore. The PERF_ROADMAP is honest about the cost: 1.86x behind Zig on image convolution, with 1.24 billion wasted instructions traced specifically to NaN-box unboxing. You cannot get C-level performance without dropping TypeScript semantics, and dropping them means you are no longer compiling TypeScript.

  • I think you mean you can't get that performance without monomorphization. When you know the types you can...

    ...wait, I went and looked up that file.

    "The Three Optimizations That Would Close the Gap"

    You're presenting the data from there in an extremely misleading way! They in no way need to drop any Typescript semantics to go faster.

    • Typescript is a dynamic language. Without changing the language, there is fundamentaly no way to resolve at compile time decisions that can be made only at runtime (ie, they are data driven). Monomorphization helps pin down (some) dynamic types but the fundamental problem remains.

      5 replies →

    • You're right. The typed buffer locals optimization keeps TypeScript semantics intact by exploiting the existing Buffer/Uint8Array type annotation to skip the NaN-unbox. It's not dropping types, it's using them. The floor I described applies to any-typed paths where static type info isn't available. For well-typed TypeScript, the roadmap shows the gap closes without semantic changes.

      1 reply →

I'm not against AI usage but the website, documentation, and even the comments the creator (proggeramlug) makes in response to questions are all very clearly AI-generated. Also, as someone else noticed, the pacing of the commits is eerily fast. That combined with the level of functionality makes me dubious how much accountability the creators have over the implementation.

Like you really built a backend that lowers to LLVM, integrated it with a generational gc, wrote a cross-platform reactive runtime, and built support for eleven different targets within like a year? Are you just prompting the model to tack on the next coolest thing or do you understand how these features work?

I worry how many of these kinds of projects will show up now. How do you guarantee stability? If there's a memory corruption error in the GC implementation, who's going to debug it?

  • This is how software development works now. We have to live with it.

    The models are good enough that this works.

    You can keep disagreeing for a while, but know that almost all the code in the industry is written like this now.

    • Trust of a project long term always was and continues to be of concern when choosing a critical dependency .

      The concern basically boils down to how large and serious is the team and what if they abandon the project in few weeks or months .

      These were always the risks, many here have been burned by betting years of their career building against promising but what turned out to be weak projects

      OP is alluding to the fact that today commit frequency, lines of code or how active the contributors in the issue trackers are no longer good signals to use as proxy.

      When the underlying project to yours is few million lines of code written by machines only it is not going to be feasible fork and maintain or in-house it if the maintainers abandon it

      To be clear users of a library or a tool aren’t owed anything when it available gratis and fully open source .

      However not everyone has access to unlimited tokens to disregard the quality (in terms of history and usage ) or size of the underlying project completely

      2 replies →

    • I have used AI agents extensively for coding and my experience is that it's fine for prototypes, but in large projects like this there is risk that the codebase becomes unmaintainable.

      2 replies →

    • Not at all, I can assert that the Spring code on my current project is classical programming.

      In many places AI tools aren't even allowed to touch customer repos.

the claim of "no runtime" is a bit dubious... you're telling me that you're statically linking a full, modern UI library into every app?

A very interesting project because I always thought TypeScript or at least some subset of it should be natively compiled.

It looks like others had a similar idea too, adding a "sound mode" to TypeScript, such as this project which is converting tsgo to Rust, also with LLMs.

https://tsz.dev/

  • Just a clarification that tsz is not a port of tsgo or tsc. It's an entirely different architecture. Inspired by Chalk and Salsa it does all of the type computations to a solver crate that does not know about the AST. This allows me to do very fast type equity and assignability computations without carrying the weight of AST nodes while walking the type graph etc.

    It's already showing results that is nearly 3x faster than tsgo. For multi-file large projects I have some ideas to implement to make it faster there too.

    Once tsz is fast and stable I'll shift focus on making sound mode a reality.

  • > such as this project which is converting tsgo to Rust

    If you'd like to follow, here's my attempt at converting tsgo to typescript (called tsts [1]). Admittedly there's AI involved, but it's a very mechanical job. Going from golang to ts is not a very difficult problem, the other way around would have been way harder. The plan is to then compile tsts to binary via tsonic.

    [1]: https://github.com/tsoniclang/tsts

    • Interesting, seems to be a very roundabout way of doing it. Have you tried compiling the current TypeScript implementation which is still in TypeScript, as tsgo is for TS 7? If so, what were the results?

      1 reply →

It would be super cool, if we can get this to compile the typescript compiler and see how fast it is against the go version.

P.S: does it have PGO for collapsing numbers to ints when possible etc

Why is this on the front page of Hacker News? Isn't it just more vibe-coded garbage where nobody takes responsibility for the resulting code?

Curious where on spectrum compiling to wasm falls between art project & optimization potential. Should be able to make some nice interfaces between TS-wasm & TS-web

> Traditional OOP runtimes use vtables for method resolution, adding a layer of indirection on every call. Perry resolves all method calls statically during compilation, turning interface method calls into direct jumps.

What? How is this possible, even with something as simple as:

  interface Animal {
    speak(): string;
  }
  
  class Cat implements Animal {}  
  class Dog implements Animal {}

  function makeSound(animal: Animal) {
    return animal.speak();
  }

  • You can just generate the 'vtable' as code :)

      switch (animal.type)
        case Cat: return cat_speak()
        case Dog: return dog_speak()
    
    

    The generated code has the functions resolved in compile time, there's no function pointer lookup in a table happening. I don't know if this is how this project does it, but this is the commonly used technique when you want to do this.

    • Hmm yeah good point. I didn't think of it. It might even be cheaper to do this when the list of possible types are closed and few.

      I am still inclined to believe AI just made up the documentation though, because this has its own tradeoffs.

      1 reply →

  • It's not possible, it reduces to the halting problem, unless you start restricting the Javascript/Typescript you allow.

    Otherwise the best you can do is be solid on common special cases. Which is what a modern (non-static) JS/TS runtime is.

> 0 ms Startup time

Is that true? It just goes right into the code with no initialization of any other libraries needed?

Browsing through the repo, I noticed this, and wondered if that isn't a recipe for disaster (code is condensed to showcase my concern)?

  app.get('/api/auth/callback', async (request: any, reply: any) => {
    const params: any = request.query || {};
    const code = params.code || '';
    const state = params.state || '';
    // Exchange code for token via curl
    const tokenResult = curlExec(
      'curl -s -X POST "https://github.com/login/oauth/access_token" -H "Accept: application/json" -d "client_id=' + GITHUB_CLIENT_ID + '&client_secret=' + GITHUB_CLIENT_SECRET + '&code=' + code + '"'
    );

Shell injection?

Perry definitely looks interesting, was just looking at getting one of these to include into my framework.

Would love to see more about it, or see more about the actual compiler docs.

While the UI framework part is neat, I prefer not to force everything into TS. Combining it means UI definitions and semantics get mixed into AST, making the unbundling of them a humongous task in itself.

Exactly the reason I built my own with pretty similar native UI semantics which supports Rust, Go, Kotlin and more (https://hypen.space) - would love to integrate Perry with it to compile TS apps directly into the runtime - but while the idea itself is great, looking at the documentation makes it hard to implement, and a lot of parts seem confusing.

Can I just use the compiler without the rest of the framework? What is the architecture? What are the limits?

After digging through the documentation, I'm unfortunately just more confused honestly. There are dozens of packages and slop markdown files such as `BUG_STRING_COMPARISON.md` and or `PERRY_UI_IMPLEMENTATION.md` which is an instruction file left for the LLM that just makes me trust the project less.

So while the idea is cool and the performance seems cool, the AI slop presentation would definitely need improvement. Adding a human touch would make it much, much better, as one could actually understand what they are dealing with.

I'm confused by the (frankly bad) documentation. It says that for pure js dependencies we need to use the v8 flag to bring in the runtime (which is undesirable), but what is the practical difference between a js file and the same file with .ts extension and explicit *any* type in every signature? Does this mean that we have to be very careful how we write our typescript to avoid v8 (and if yes, how? I couldn't find that on the site) or does it mean that we can get away with transpiling everything to ts with loose typing? I suspect it's the first, in which case it's literally the most important information that anyone using Perry needs to know, and it should be one of the first things mentioned in their AI-vibed page.