A standard library for the client-side Web

The goal of this crate is to provide Rust bindings to the Web APIs and to allow a high degree of interoperability between Rust and JavaScript.

Examples

You can directly embed JavaScript code into Rust:

```rust let message = "Hello, 世界!"; let result = js! { alert!( @{message} ); return 2 + 2 * 2; };

println!( "2 + 2 * 2 = {:?}", result ); ```

Even closures are are supported:

```rust let print_hello = |name: String| { println!( "Hello, {}!", name ); };

js! { var printhello = @{printhello}; printhello( "Bob" ); printhello.drop(); // Necessary to clean up the closure on Rust's side. } ```

You can also pass arbitrary structures thanks to [serde]:

```rust

[derive(Serialize)]

struct Person { name: String, age: i32 }

js_serializable!( Person );

js! { var person = @{person}; console.log( person.name + " is " + person.age + " years old." ); }; ```

This crate also exposes a number of Web APIs, for example:

rust let button = document().query_selector( "#hide-button" ).unwrap(); button.add_event_listener( move |_: ClickEvent| { for anchor in document().query_selector_all( "#main a" ) { js!( @{anchor}.style = "display: none;"; ); } });

Design goals

• Expose a full suite of Web APIs as exposed by web browsers.
• Try to follow the original JavaScript conventions and structure as much as possible, except in cases where doing otherwise results in a clearly superior design.
• Be a building block from which higher level frameworks and libraries can be built.
• Make it convenient and easy to embed JavaScript code directly into Rust and to marshal data between the two.
• Integrate with the wider Rust ecosystem, e.g. support marshaling of structs which implement serde's Serializable.
• Put Rust in the driver's seat where a non-trivial Web application can be written without touching JavaScript at all.
• Allow Rust to take part in the upcoming WebAssembly (re)volution.

Getting started

WARNING: This crate is still a work-in-progress. Things might not work. Things might break. The APIs are in flux. Please do not use it in production.

1. Add an asmjs target with rustup:

   $ rustup target add asmjs-unknown-emscripten

2. Install emscripten. If you're on Arch Linux then you can just run sudo pacman -S emscripten; other distributions might also have recent enough emscripten packages in their repositories.

   Alternatively you can install it like this:

   $ curl -O https://s3.amazonaws.com/mozilla-games/emscripten/releases/emsdk-portable.tar.gz $ tar -xzf emsdk-portable.tar.gz $ source emsdkportable/emsdkenv.sh $ emsdk update $ emsdk install sdk-incoming-64bit $ emsdk activate sdk-incoming-64bit

3. Install [cargo-web]; it's not strictly necessary but it makes things more convenient:

   $ cargo install cargo-web

4. Go into examples/todomvc and type:

   $ cargo web start

5. Visit http://localhost:8000 with your browser.

License

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.

Snippets of documentation which come from [Mozilla Developer Network] are covered under the [CC-BY-SA, version 2.5] or later.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.