3f85d7db9f
This commit removes the need for an injected `ConstructorToken` type and also cleans up the story we have for generating constructors a bit. After this commit a `constructor()` is omitted entirely if we're in non-debug mode and there's no actual listed constructor. Additionally we don't deal with splat arguments and rerouting constructors, Nick was kind enough to enlighten me about `Object.create` which is creating an instance without running the constructor! Instances of an exported type are now created through one of two methods: * If `#[wasm_bindgen(constructor)]` is present, then a `constructor` is generated with the appropriate signature. If a constructor is not present and we're in debug mode, a throwing constructor is generated. If we're in release mode and there's no constructor, no constructor is generated. * Otherwise if a binding returns an instance of a type (or otherwise needs to manfuacture an instance, then it will cause an internal `__wrap` function to be generated. This function will use `Object.create` to create an instance without running the constructor. This should ideally clean up our generated JS for classes quite a bit, making it much more lean-and-mean!
wasm-bindgen
Facilitating high-level interactions between wasm modules and JavaScript.
Import JavaScript things into Rust and export Rust things to JavaScript.
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
// Import the `window.alert` function from the Web.
#[wasm_bindgen]
extern {
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 "host 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! 📚
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.