d5d3e46334
After this change, any import that only takes and returns ABI-safe numbers (signed
integers less than 64 bits and unrestricted floating point numbers) will be a
direct import, and will not have a little JS shim in the middle.
We don't have a great mechanism for testing the generated bindings' contents --
as opposed to its behavior -- but I manually verified that everything here does
the Right Thing and doesn't have a JS shim:
```rust
\#[wasm_bindgen]
extern "C" {
fn trivial();
fn incoming_i32() -> i32;
fn incoming_f32() -> f32;
fn incoming_f64() -> f64;
fn outgoing_i32(x: i32);
fn outgoing_f32(y: f32);
fn outgoing_f64(z: f64);
fn many(x: i32, y: f32, z: f64) -> i32;
}
```
Furthermore, I verified that when our support for emitting native `anyref` is
enabled, then we do not have a JS shim for the following import, but if it is
disabled, then we do have a JS shim:
```rust
\#[wasm_bindgen]
extern "C" {
fn works_when_anyref_support_is_enabled(v: JsValue) -> JsValue;
}
```
Fixes #1636.
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.