A tiny crate of utilities for working with implicit Wasm codegen conventions (often established by LLVM and lld).

Examples conventions include:

• The stack pointer
• The canonical linear memory that contains the stack

Install wasm-bindgen-cli

You can install it using cargo install:

cargo install wasm-bindgen-cli

Or, you can download it from the release page.

If you have cargo-binstall installed, then you can install the pre-built artifacts by running:

cargo binstall wasm-bindgen-cli

Example

Import JavaScript things into Rust and export Rust things to JavaScript.

use wasm_bindgen::prelude::*;

// Import the `window.alert` function from the Web.
#[wasm_bindgen]
extern "C" {
    fn alert(s: &str);
}

// Export a `greet` function from Rust to JavaScript, that alerts a
// hello message.
#[wasm_bindgen]
pub fn greet(name: &str) {
    alert(&format!("Hello, {}!", name));
}

Use exported Rust things from JavaScript with ECMAScript modules!

import { greet } from "./hello_world";

greet("World!");

Features

• Lightweight. Only pay for what you use. wasm-bindgen only generates bindings and glue for the JavaScript imports you actually use and Rust functionality that you export. For example, importing and using the document.querySelector method doesn't cause Node.prototype.appendChild or window.alert to be included in the bindings as well.

• ECMAScript modules. Just import WebAssembly modules the same way you would import JavaScript modules. Future compatible with WebAssembly modules and ECMAScript modules integration.

• Designed with the "Web IDL bindings" proposal in mind. Eventually, there won't be any JavaScript shims between Rust-generated wasm functions and native DOM methods. Because the Wasm functions are statically type checked, some of those native methods' dynamic type checks should become unnecessary, promising to unlock even-faster-than-JavaScript DOM access.

Guide

📚 Read the wasm-bindgen guide here! 📚

You can find general documentation about using Rust and WebAssembly together here.

API Docs

• wasm-bindgen
• js-sys
• web-sys
• wasm-bindgen-futures

MSRV Policy

Libraries that are released on crates.io have a MSRV of v1.57. Changes to the MSRV will be accompanied by a minor version bump.

CLI tools and their corresponding support libraries have a MSRV of v1.76. Changes to the MSRV will be accompanied by a patch version bump.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

See the "Contributing" section of the guide for information on hacking on wasm-bindgen!

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.