Running JavaScript in Rust with Deno: Experimenting with Deno's Rust Crates (opens in new tab)

(austinpoor.com)

136 pointsa-poor2y ago19 comments

19 comments

Being able to allow custom behaviour via JS/TS in Rust is definitely something that I wanted to explore too. If you haven’t already you should check out these two articles from the Deno blog website which go a bit further:

https://deno.com/blog/roll-your-own-javascript-runtime

https://deno.com/blog/roll-your-own-javascript-runtime-pt2

dcdunkan2y ago

Part 3 of the series was published just an hour ago:

https://deno.com/blog/roll-your-own-javascript-runtime-pt3

smt882y ago

> Being able to allow custom behaviour via JS/TS in Rust

I understanding wanting to call out to Rust from JS/TS, but I don't think I understand wanting the reverse. Isn't a major goal of Rust not to have "custom behavior" that is invisible to the compiler?

fndex2y ago

Imagine you are building a game in Rust where players can write mods. Those mods could be written in JS/TS while the game is written in Rust.

1 more reply

gabereiser2y ago

Building a data ingestion pipeline that scales horizontally but leaves the ingestion rules up to your customer in the form of a ts module that implements an interface? There’s plenty of opportunities to allow your runtime to be controlled via scripting.

Or a function host that executes jobs at scale? You only need to program the security, sandboxing, scheduling, and distribution of functions that can be invoked.

vanjajaja12y ago

Presumably Deno is a use case where you would want to write rust that hosts js/ts safely

nerdix2y ago

Some applications use Lua for configuration: neovim, conky, awesome, etc.

I haven't looked into the details of this so I'm not sure if its a suitable replacement for embedding lua (binary size would be my first concern..does this embed v8?) But I would much prefer TypeScript as a configuration language than Lua.

pkulak2y ago

Business apps can sometimes be so complicated that the decision is between having a giant settings page, where you try to anticipate everything users will want to do, or you let them write little snippets of code that you interpret on the fly. I like the latter approach a lot, because even if I have to help write the snippets, it’s easier than shoving special-case code into the project, yet again, and deploying.

izietto2y ago

I'm trying to build a view rendering engine / perform SSR straight on Rust with that

1 more reply

JLCarveth2y ago

I wasn't aware of a pt2, thanks for the link.

1 more reply

rubenfiszel2y ago

> Data pipelines (eg Apache Airflow) where the orchestration is handled by Rust but the high-level business logic is defined using JavaScript

That is ... exactly what windmill is https://github.com/windmill-labs/windmill

The orchestrator is built from scratch in rust using postgresql to store the state. The steps when in typescript are run in deno: https://github.com/windmill-labs/windmill/blob/main/backend/... and the transforms between the steps (piping outputs of any node to the input of any node) are actually javascript expressions run by deno JsRuntimes: https://github.com/windmill-labs/windmill/blob/f3ec9ca09dc37...

Narew2y ago

Maybe a naive question but why using Deno instead of v8 directly for javascript interpreter/compiler/runtime, it can also be called from rust.

brabel2y ago

> the release build of js-in-rs is 54 MB, grep is 179 KB, and a basic hello world JS application compiled using Deno is 103 MB.

OMG. That's ridiculous.

Write the code in C or Zig, and use Lua for scripting, and you're down to under 1MB for the final binary.

j / k navigate · click thread line to collapse

19 comments

quentinadam2y ago

https://deno.com/blog/roll-your-own-javascript-runtime

https://deno.com/blog/roll-your-own-javascript-runtime-pt2

dcdunkan2y ago

Part 3 of the series was published just an hour ago:

https://deno.com/blog/roll-your-own-javascript-runtime-pt3

smt882y ago

> Being able to allow custom behaviour via JS/TS in Rust

I understanding wanting to call out to Rust from JS/TS, but I don't think I understand wanting the reverse. Isn't a major goal of Rust not to have "custom behavior" that is invisible to the compiler?

fndex2y ago

Imagine you are building a game in Rust where players can write mods. Those mods could be written in JS/TS while the game is written in Rust.

1 more reply

gabereiser2y ago

Or a function host that executes jobs at scale? You only need to program the security, sandboxing, scheduling, and distribution of functions that can be invoked.

vanjajaja12y ago

Presumably Deno is a use case where you would want to write rust that hosts js/ts safely

nerdix2y ago

Some applications use Lua for configuration: neovim, conky, awesome, etc.

pkulak2y ago

izietto2y ago

I'm trying to build a view rendering engine / perform SSR straight on Rust with that

1 more reply

JLCarveth2y ago

I wasn't aware of a pt2, thanks for the link.

1 more reply

rubenfiszel2y ago

> Data pipelines (eg Apache Airflow) where the orchestration is handled by Rust but the high-level business logic is defined using JavaScript

That is ... exactly what windmill is https://github.com/windmill-labs/windmill

Narew2y ago

Maybe a naive question but why using Deno instead of v8 directly for javascript interpreter/compiler/runtime, it can also be called from rust.

brabel2y ago

> the release build of js-in-rs is 54 MB, grep is 179 KB, and a basic hello world JS application compiled using Deno is 103 MB.

OMG. That's ridiculous.

Write the code in C or Zig, and use Lua for scripting, and you're down to under 1MB for the final binary.

j / k navigate · click thread line to collapse