# 📦✨ wasm-pack
> Your favorite rust -> wasm workflow tool!
[](https://travis-ci.org/rustwasm/wasm-pack)
[](https://ci.appveyor.com/project/rustwasm/wasm-pack)
This tool seeks to be a one-stop shop for building and working with rust-
generated WebAssembly that you would like to interop with JavaScript, in the
browser or with Node.js. `wasm-pack` helps you build and publish rust-generated
WebAssembly to the npm registry to be used alongside any other javascript
package in workflows that you already use, such as a bundler like
[webpack] or [greenkeeper].
[bundler-support]: https://github.com/rustwasm/team/blob/master/goals/bundler-integration.md#details
[webpack]: https://webpack.js.org/
[greenkeeper]: https://greenkeeper.io/
This project is a part of the [rust-wasm] group. You can find more info by
visiting that repo!
[rust-wasm]: https://github.com/rustwasm/team
## 🔮 Prerequisities
- [Development Environment](docs/prerequisites.md)
- [Installation and Getting Started](docs/setup.md)
## 🎙️ Commands
- [`init`](docs/init.md): Generate an npm wasm pkg from a rustwasm crate
- [`pack`](docs/pack.md): Create a tarball of your rustwasm pkg
- [`publish`](docs/publish.md): Publish your rustwasm pkg to a registry
## 📝 Logging
We generate a `wasm-pack.log` file if `wasm-pack` errors on you, and you can
customize the log verbosity using the verbosity flag.
| -v | All Info, Warn, and Errors are logged |
| -vv | All Debug, Info, Warn, and Errors are logged |
| -vvv | All Trace, Debug, Info, Warn, and Errors are logged |
## 👯 Contributing
Read our [guide] on getting up and running for developing `wasm-pack`, and
check out our [contribution policy].
[guide]: docs/contributing.md
[contribution policy]: CONTRIBUTING.md
## ⚡ Quickstart Guide
1. Write a crate in Rust.
2. Add `wasm-bindgen` to your `Cargo.toml`:
```toml
[lib]
crate-type = ["cdylib"]
[dependencies]
wasm-bindgen = "0.2"
```
3. Add this to the top of your `src/lib.rs`:
```rust
#![feature(proc_macro, wasm_import_module, wasm_custom_section)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
```
4. Annotate your public functions with `#[wasm_bindgen]`, for example:
```rust
#[wasm_bindgen]
extern {
pub fn alert(s: &str);
}
#[wasm_bindgen]
pub fn greet(name: &str) {
alert(&format!("Hello, {}!", name));
}
```
5. Install this tool: `cargo install wasm-pack`
6. Run `wasm-pack init`, optionally, pass a path to a dir or a scope (see above for details)
7. This tool generates files in a `pkg` dir
8. To publish to npm, run `wasm-pack publish`. You may need to login to the
registry you want to publish to. You can login using `wasm-pack login`.
[rust-wasm/36]: https://github.com/rustwasm/team/issues/36
[wasm-bindgen]: https://github.com/alexcrichton/wasm-bindgen
