f749c7cf95
This commit migrates away from using Serde for the custom section in wasm executables. This is a refactoring of a purely-internal data structure to `wasm-bindgen` and should have no visible functional change on users. The motivation for this commit is two fold: * First, the compile times using `serde_json` and `serde_derive` for the syntax extension isn't the most fun. * Second, eventually we're going to want to stablize the layout of the custom section, and it's highly unlikely to be json! Primarily, though, the intention of this commit is to improve the cold-cache compile time of `wasm-bindgen` by ensuring that for new users this project builds as quickly as possible. By removing some heavyweight dependencies from the procedural macro, `serde`, `serde_derive`, and `serde_json`, we're able to get a pretty nice build time improvement for the `wasm-bindgen` crate itself: | | single-core build | parallel build | |-------------|-------------------|----------------| | master | 36.5s | 17.3s | | this commit | 20.5s | 11.8s | These are't really end-all-be-all wins but they're much better especially on the spectrum of weaker CPUs (in theory modeled by the single-core case showing we have 42% less CPU work in theory).
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.