rollup-plugin-rust

^{^{tl;dr -- see examples}}

This is a rollup plugin that loads Rust code so it can be interop with Javascript base project. Currently, the Rust code will be compiled as:

WebAssembly module/instance
Node.js addon/ffi

Requirements

Node v8 or later
Rollup v0.64 or later

Rust v1.28.0 with wasm32-uknown-unknown installed

rustup default 1.28.0
rustup target add wasm32-unknown-unknown

This module requires a minimum of Node v8.9.0, Rollup v0.64.0, and Rust in [nightly channel][].

Getting Started

To begin, you'll need to install rollup-plugin-rust:

npm install rollup-plugin-rust --save-dev

Then add the plugin to your rollup config. For example:

rollup.config.js

import rust from "rollup-plugin-rust";
 
export default [
  {
    input: "src/main.js",
    output: {
      file: "dist.index.js",
      format: "esm"
    },
    plugins: [rust()]
  }
];

quick usage

lib.rs

#[no_mangle]
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

index.js

import wasm from "lib.rs";
 
export async function increment(a) {
  const { instance } = await wasm;
  return instance.exports.add(1, a);
}

And run rollup via your preferred method.

Options

export

How wasm code would be exported. This options is identical with option export in webassembly-loader. (see examples)

// in your rollup.config.js
{
  plugins: [rust({ export: "instance" })];
}

target

Type: String
Default: wasm32-unknown-unknown
Expected value: see supported platform

The Rust target to use. Currently it only support wasm related target

// in your rollup.config.js
{
  plugins: [rust({ target: "wasm32-unknown-emscripten" })];
}

release

Type: Boolean
Default: true

Whether to compile the Rust code in debug or release mode.

// in your rollup.config.js
{
  plugins: [rust({ release: false })]; // preserve debug symbol
}

include

Type: Array<string> or string
Default: ['**/*.rs']

A single file, or array of files, to include when compiling.

// in your rollup.config.js
{
  plugins: [
    rust({
      include: ["src/**/*.rs", "test/**/*.rs"]
    })
  ];
}

exclude

Type: Array<string> or string
Default: ['node_modules/**', 'target/**']

A single file, or array of files, to exclude when linting.

// in your rollup.config.js
{
  plugins: [
    rust({
      exclude: ["**/node_modules/**", "**/target/**", "**/__caches__/**"]
    })
  ];
}

Examples

See the test cases and example projects in fixtures and examples for more insight.

TL;DR

Given this Rust code

lib.rs

#[no_mangle]
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

Cargo.toml

[package]
name = "adder"
version = "0.1.0"
authors = ["Full Name <email@site.domain>"]
 
[lib]
crate-type = ["cdylib"]
path = "lib.rs"

With options

`{export: 'buffer'}`

import wasmCode from "./lib.rs";
 
WebAssembly.compile(wasmCode).then(module => {
  const instance = new WebAssembly.Instance(module);
  console(instance.exports.add(1, 2)); // 3
});

`{export: 'module'}`

import wasmModule from "./lib.rs";
 
const instance = new WebAssembly.Instance(wasmModule);
console(instance.exports.add(1, 2)); // 3

`{export: 'instance'}`

import wasm from "./lib.rs";
 
console(wasm.exports.add(1, 2)); // 3

`{export: 'async'}`

extern {
    fn hook(c: i32);
}
 
#[no_mangle]
pub fn add(a: i32, b: i32) -> i32 {
    hook(a + b)
}

import wasmInstantiate from "./lib.rs";
 
wasmInstantiate(importObject | undefined).then(({ instance, module }) => {
  console(instance.exports.add(1, 2)); // 3
 
  // create different instance, extra will be called in different environment
  const differentInstance = new WebAssembly.Instance(module, {
    env: {
      hook: result => result * 2
    }
  });
  console(differentInstance.exports.add(1, 2)); // 6
});

`{export: 'async-instance'}`

import wasmInstantiate from "./lib.rs";
 
wasmInstantiate(importObject | undefined).then(instance => {
  console(instance.exports.add(1, 2)); // 3
});

`{export: 'async-module'}`

import wasmInstantiate from "./lib.rs";
 
wasmCompile(importObject | undefined).then(module => {
  const differentInstance = new WebAssembly.Instance(module);
  console(differentInstance.exports.add(1, 2)); // 3
});