745b16e3d2
This commit adds support for the recently implemented standard of [`TextEncoder#encodeInto`][standard]. This new function is a "bring your own buffer" style function where we can avoid an intermediate allocation and copy by encoding strings directly into wasm's memory. Currently we feature-detect whether `encodeInto` exists as it is only implemented in recent browsers and not in all browsers. Additionally this commit emits the binding using `encodeInto` by default, but this requires `realloc` functionality to be exposed by the wasm module. Measured locally an empty binary which takes `&str` previously took 7.6k, but after this commit takes 8.7k due to the extra code needed for `realloc`. [standard]: https://encoding.spec.whatwg.org/#dom-textencoder-encodeinto Closes #1172 |
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| .cargo | ||
| crates | ||
| examples | ||
| guide | ||
| releases | ||
| src | ||
| tests | ||
| .appveyor.yml | ||
| .gitattributes | ||
| .gitignore | ||
| .travis.yml | ||
| build.rs | ||
| Cargo.toml | ||
| CHANGELOG.md | ||
| CONTRIBUTING.md | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| package.json | ||
| publish.rs | ||
| README.md | ||
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 "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 "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.