Facilitating high-level interactions between Wasm modules and JavaScript
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Alex Crichton f749c7cf95 Don't use JSON for custom section format
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).
2018-10-12 11:23:00 -07:00
.cargo Start running CI tests on Rust beta 2018-09-25 10:36:28 -07:00
crates Don't use JSON for custom section format 2018-10-12 11:23:00 -07:00
examples Fix unimportant typo 2018-10-06 21:09:18 +02:00
guide Add caveat for BigInt and u64 in browser support 2018-10-10 10:30:32 -07:00
releases Add a template for release announcements 2018-06-19 12:05:52 -07:00
src Ensure that JsValue isn't considered Send 2018-10-10 15:47:07 -07:00
tests Fix generated shims if APIs don't exist 2018-10-10 17:46:51 -07:00
.appveyor.yml Remove some crufty AppVeyor configuration 2018-09-12 11:08:19 -07:00
.gitattributes add .gitattributes to mark WebIDL as vendored 2018-07-11 18:48:51 -04:00
.gitignore Bump to 0.2.18 2018-08-27 13:37:55 -07:00
.travis.yml Merge pull request #881 from alexcrichton/test-beta 2018-09-25 12:27:41 -07:00
build.rs Implement AsRef<JsValue> for Closure<T> 2018-09-06 14:46:59 -07:00
Cargo.toml Bump to 0.2.25 2018-10-10 13:19:40 -07:00
CHANGELOG.md Bump to 0.2.25 2018-10-10 13:19:40 -07:00
CONTRIBUTING.md Fix contributing URL 2018-09-20 17:37:04 -07:00
LICENSE-APACHE Add license texts 2017-12-18 14:45:06 -08:00
LICENSE-MIT Add license texts 2017-12-18 14:45:06 -08:00
package.json Fix polyfill of TextEncoder and TextDecoder 2018-09-30 10:16:20 -07:00
publish.rs Bump to 0.2.25 2018-10-10 13:19:40 -07:00
README.md Fix broken link to contribution page 2018-10-05 10:25:55 -05:00

wasm-bindgen

Facilitating high-level interactions between wasm modules and JavaScript.

Build Status Build status API Documentation on docs.rs

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-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 "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

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.