Bonsai: Janestreet's UI Library

flufluflufluffy•about 1 hour ago

> And because Bonsai is written in OCaml, it becomes possible to use the same language and types on both the backend and frontend.

Finally! I was waiting for this to become possible!

philipwhiuk•5 minutes ago

Similar attempts include Scalajs.

The general challenge becomes integrating the fractional front-end code written in your backend-language that compiles to JS with the rest of the JS ecosystem.

JaneStreet have a love of writing their own stuff from scratch so it doesn't apply to them but it might to you.

Hence most people end up with frontend-as-backend rather than backend-as-frontend.

xvilka•about 2 hours ago

Looks like it's Web-only, no mention of the native UI support (terminal UI excluded).

avsm•about 1 hour ago

There's a full terminal implementation of Bonsai as well. I actually use it in my personal workflow these days to manage my contacts database! https://anil.recoil.org/notes/aoah-2025-9

bobjansen•about 1 hour ago

This would of been cool back in 2014.

kubb•about 1 hour ago

I wish there were more OCaml shops out there

hahahaa•about 2 hours ago

Oh it needs a userland trampoline!

> JSOO does not have tail call optimization

Traster•about 2 hours ago

The "Why Bonsai?" I found really funny.

Let me re-write that section for you:

Why Bonsai?

At Jane Street we're super excited by Functional programming and by CAML in particular, so when we need low latency software, we use OCAML, when we need hardware, we write out own langauge - HardCAML, and when we need a Web UI, we build a Web UI framework in CAML. Because we fucking love CAML.

bofeiw•about 1 hour ago

Agreed, looks like it's reinventing the wheels. Frameworks does not really matter today, AI agents write the code anyway.

KolmogorovComp•about 1 hour ago

But AI do benefit a lot from a strict compiler, and having a simple language improve a lot on type-safety, so I don't think it is to throw, even today.

rmzs0711•about 1 hour ago

But what about compilation speed? Hot reload? Maintainability? What is the bus factor for these kind of technologies?

Yea, its cool to have strict type safety, but what's the point of it doesn't have all the benefits from other Frameworks that took years to polish

ForHackernews•about 1 hour ago

Better frameworks will still help AIs avoid silly mistakes. A smarter framework means you can be productive with a dumber/cheaper AI.

Bonsai: Janestreet's UI Library

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