Create a project template for writing wasm libraries intended for use by JS

[fitzgen]

It should have

• the state-of-the-art dependencies already in Cargo.toml
• extern declarations for those crates already in src/lib.rs
• #![no_std] declaration
• panic_fmt handler that doesn't use fmting infrastructure, for small code sizes by default
• some script or makefile or xargo type thing that does cargo build --release wasm32-unknown-unknown && wasm-gc ... && wasm-opt ...

Open questions:

• Where should this template live? A new repository?
• What dependencies should it come with?
  • wasm-bindgen? This seems like a good choice to me.
  • wee_alloc as the global allocator? This is much more opinionated, and is likely not the right choice in many situations, but in the library-for-use-by-JS scenario fairly likely to be a good choice.
  • Other things?

[mgattozzi]

A while back I had started doing something called cargo-wasm and the idea was eventually use that for building stuff and wrapping the commands needed every time to do it/deal with all the weird manual stuff when setting things up. It might be possible to work out some stuff and create a small config, kind of like xargo does, and have it initialize a project based off it. I might have time to hack in a prototype

Ideally I really wish cargo just had inbuilt templates/automatically choosing a specified target but that's a road that's been fraught with contention for some time and I don't think an RFC has really been pushed through to do it that way.

[fitzgen]

Ideally I really wish cargo just had inbuilt templates/automatically choosing a specified target but that's a road that's been fraught with contention for some time and I don't think an RFC has really been pushed through to do it that way.

There was talk between WG domain leads about creating templates for each of our domains in our meeting yesterday, so I think the winds are changing and we can get this to happen.

[mgattozzi]

I think I and many others would be happy. It's something stack does in Haskell that I really wish Rust already had. Either way this sounds good.

[ashleygwilliams]

this sounds like a great idea! it's a bit blocked on the packaging tool which is blocked on how JS deps are expressed in wasm. to build the packaging tool i have an example template that i'm already working on - so i can help complete this as the packaging tool work moves forward :)

[fitzgen]

it's a bit blocked on the packaging tool which is blocked on how JS deps are expressed in wasm

I think we can pursue an incremental approach, where we start without packaging integration and then add it when it's ready.

so i can help complete this as the packaging tool work moves forward :)

Awesome!

[koute]

We might consider having a few different templates here, e.g. pure Rust one, wasm-bindgen-using one, cargo-web for Node.js, cargo-web for the Web through Parcel**, etc.

** - Although my main focus with stdweb and cargo-web is in supporting pure Rust webapps the use case of building JS-callable libraries is also on my agenda, e.g. I have a Parcel plugin with which you can just import a Cargo.toml into a JS frontend project (although due to code-bloat it isn't really that great), and out-of-box you can take the .js generated by cargo-web and require it from Node.js (where code bloat doesn't really matter)

[alexcrichton]

I think this is covered by https://github.com/rustwasm/wasm-pack-template!