Rust 🦀 + WebAssembly 📦 = 💝

This is a personal playground for my experimentations with Rust and WebAssembly (using wasm-pack & wasm-bindgen).

Requirements

Rust 🤷
wasm-pack
And, depending on the target platform:
- Node.js 8+, or,
- A compatible browser

Getting started

Clone the repository and execute wasm-pack build in order to generate the WebAssembly binary and its JavaScript binding as a npm module in ./pkg. The default bindings are supposed to be consumed by a bundler like Webpack. Use --target to build a module for Node.js: wasm-pack build --target nodejs.

💡 Add the parameter --release to build an optimized module.

The resulting module is already installed as a dependency (rust-wasm-introduction from ./pkg) in the two TypeScript projects: ./nodejs and ./browser. Thus, it can be imported as any regular module.

Node.js & Browser

The Wasm module is available in the two projects. Make sure you built it using the valid target, depending on the project you want to use.

Use the scripts available to build, test and start the projects (see their respective package.json).

The function naive_fibonacci has been written twice, once in Rust, once in JavaScript, to make a basic comparison of their performance in Node.js. See ./nodejs/src/naive-fibonacci.

Adding a Rust package

Consider creating a new library when you need to add a package to the output.

$ cargo new --lib --name new-fancy-lib packages/new-fancy-lib
     Created library `new-fancy-lib` package

Add wasm-bingden to its dependencies:

# packages/new-fancy-lib/Cargo.toml
[dependencies]
wasm-bindgen = "0.2"

Then declare it as a dependency of the main package:

# Cargo.toml
[dependencies]
new-fancy-lib = { version = "0.1.0", path = "packages/new-fancy-lib" }

And finally, export it from src/lib.rs.

pub use new_fancy_lib;

Compile the project again (wasm-pack build) to see the new JavaScript bindings from new-fancy-lib 🎉.

Testing a Rust package

Simply run cargo test -p with the name of the package.

$ cargo test -p bank-account
    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
     Running target/debug/deps/bank_account-87bf4d4300aefea4

running 3 tests
test tests::it_deposits_the_given_amount ... ok
test tests::it_withdraws_the_given_amount ... ok
test tests::test_negative_balance_on_withdraw ... ok

test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

💡 At the present time, I have no particular interest in using wasm_bindgen_test (and running tests with wasm-pack), but this might change in the future.

VinceOPS / rust-wasm-introduction