452ce2916e
This commit adds support to `wasm-bindgen` to be a drop-in polyfill for the WebIDL bindings proposal. Lots of internal refactoring has happened previously to `wasm-bindgen` to make this possible, so this actually ends up being a very small PR! Most of `wasm-bindgen` is geared towards Rust-specific types and Rust-specific support, but with the advent of WebIDL bindings this is a standard way for a WebAssembly module to communicate its intended interface in terms of higher level types. This PR allows `wasm-bindgen` to be a polyfill for any WebAssembly module that has a valid WebIDL bindings section, regardless of its producer. A standard WebIDL bindings section is recognized in any input wasm module and that is slurped up into wasm-bindgen's own internal data structures to get processed in the same way that all Rust imports/exports are already processed. The workflow for `wasm-bindgen` looks the same way that it does in Rust today. You'd execute `wasm-bindgen path/to/foo.wasm --out-dir .` which would output a new wasm file and a JS shim with the desired interface, and the new wasm file would be suitable for loading in MVP implementations of WebAssembly. Note that this isn't super thoroughly tested, so there's likely still some lingering assumptions that `wasm-bindgen` makes (such as `__wbindgen_malloc` and others) which will need to be patched in the future, but the intention of this commit is to start us down a road of becoming a drop-in polyfill for WebIDL bindings, regardless of the source. Also note that there's not actually any producer (AFAIK) of a WebIDL bindings custom section, so it'd be that much harder to write tests to do so!
wasm-bindgen
Facilitating high-level interactions between Wasm modules and JavaScript.
Guide | API Docs | Contributing | Chat
Built with 🦀🕸 by The Rust and WebAssembly Working Group
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-bindgenonly generates bindings and glue for the JavaScript imports you actually use and Rust functionality that you export. For example, importing and using thedocument.querySelectormethod doesn't causeNode.prototype.appendChildorwindow.alertto 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
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.