rust-wasm

A Rust and JavaScript utility suite for writing WebAssembly modules.

• Write functions with near-automatic string handling and memory management
• Ergonomic memory management API if you want to avoid unnecessary allocations
• No additional build-time tools required—use Cargo and your JavaScript bundler

Note: This is in early stages, expect frequent API changes for now.

lib.rs

extern crate rust_wasm_prelude;
use rust_wasm_prelude::*;

pub use rust_wasm_prelude::exports::*;

#[no_mangle]
pub fn to_uppercase(ptr: JsString) -> JsString {
    let mut s: String = js_string_input(ptr);
    s = s.to_uppercase();
    js_string_output(s)
}

index.js

import { Prelude, types } from '@rust-wasm/prelude'
import loadWasm from './lib.rs'

const prelude = new Prelude()

loadWasm()
  .then(module => module.instance.exports)
  .then(exports => {
    prelude.withExports(exports)

    const toUppercase = prelude.wrap(
      types.string,
      types.string,
      exports.to_uppercase
    )

    console.log('uppercase of `test` is', toUppercase('test'))
  })

Installation

Add Rust dependency to your Cargo.toml

rust-wasm-prelude = "0.3.0"
rust-wasm-utils = "0.3.0"

Install JavaScript dependency with yarn/npm

yarn add @rust-wasm/prelude @rust-wasm/utils

Examples

• Basic: A buildable demo project showing the API essentials
• Memory Management: The same as basic, but shows how to manage memory manually on the JS side

Acknowledgements

• HelloRust for showing how string passing functions are used by JavaScript and Rust