# napi-rs
> This project was initialized from [xray](https://github.com/atom/xray)
A minimal library for building compiled `Node.js` add-ons in `Rust`.
_Main branch is now under napi@next developing. Checkout [v1 docs](https://napi.rs) for napi@1.x._
## Ecosystem
## Platform Support
[](https://github.com/napi-rs/napi-rs/actions/workflows/windows-arm.yml)
[](https://cirrus-ci.com/github/napi-rs/napi-rs?branch=main)
| | node12 | node14 | node16 |
| --------------------- | ------ | ------ | ------ |
| Windows x64 | ✓ | ✓ | ✓ |
| Windows x86 | ✓ | ✓ | ✓ |
| Windows arm64 | ✓ | ✓ | ✓ |
| macOS x64 | ✓ | ✓ | ✓ |
| macOS aarch64 | ✓ | ✓ | ✓ |
| Linux x64 gnu | ✓ | ✓ | ✓ |
| Linux x64 musl | ✓ | ✓ | ✓ |
| Linux aarch64 gnu | ✓ | ✓ | ✓ |
| Linux aarch64 musl | ✓ | ✓ | ✓ |
| Linux arm gnueabihf | ✓ | ✓ | ✓ |
| Linux aarch64 android | ✓ | ✓ | ✓ |
| FreeBSD x64 | ✓ | ✓ | ✓ |
This library depends on Node-API and requires `Node@10.0.0` or later.
We already have some packages written by `napi-rs`: [node-rs](https://github.com/napi-rs/node-rs)
One nice feature is that this crate allows you to build add-ons purely with the `Rust/JavaScript` toolchain and without involving `node-gyp`.
## Taste
> You can start from [package-template](https://github.com/napi-rs/package-template) to play with `napi-rs`
### Define JavaScript functions
```rust
#[macro_use]
extern crate napi;
/// import the preludes
use napi::bindgen_prelude::*;
/// module registerion is done by the runtime, no need to explicitly do it now.
#[napi]
fn fibonacci(n: u32) -> u32 {
match n {
1 | 2 => 1,
_ => fibonacci(n - 1) + fibonacci(n - 2),
}
}
/// use `Fn`, `FnMut` or `FnOnce` traits to defined JavaScript callbacks
/// the return type of callbacks can only be `Result`.
#[napi]
fn get_cwd Result<()>>(callback: T) {
callback(env::current_dir().unwrap().to_string_lossy().to_string()).unwrap();
}
/// or, define the callback signature in where clause
#[napi]
fn test_callback(callback: T)
where T: Fn(String) -> Result<()>
{}
/// async fn, require `async` feature enabled.
/// [dependencies]
/// napi = {version="2", features=["async"]}
#[napi]
async fn read_file_async(path: String) -> Result {
tokio::fs::read(path)
.map(|r| match r {
Ok(content) => Ok(content.into()),
Err(e) => Err(Error::new(
Status::GenericFailure,
format!("failed to read file, {}", e),
)),
})
.await
}
```
more examples at [examples](./examples/napi)
## Building
This repository is a `Cargo` crate. Any napi-based add-on should contain `Cargo.toml` to make it a Cargo crate.
In your `Cargo.toml` you need to set the `crate-type` to `"cdylib"` so that cargo builds a C-style shared library that can be dynamically loaded by the Node executable. You'll also need to add this crate as a dependency.
```toml
[package]
name = "awesome"
[lib]
crate-type = ["cdylib"]
[dependencies]
napi = "2"
napi-derive = "2"
[build-dependencies]
napi-build = "1"
```
And create `build.rs` in your own project:
```rust
// build.rs
extern crate napi_build;
fn main() {
napi_build::setup();
}
```
So far, the `napi` build script has only been tested on `macOS` `Linux` `Windows x64 MSVC` and `FreeBSD`.
Install the `@napi-rs/cli` to help you build your `Rust` codes and copy `Dynamic lib` file to `.node` file in case you can `require` it in your program.
```js
{
"package": "awesome-package",
"devDependencies": {
"@napi-rs/cli": "^1.0.0"
},
"napi": {
"name": "jarvis" // <----------- Config the name of native addon, or the napi command will use the name of `Cargo.toml` for the binary file name.
},
"scripts": {
"build": "napi build --release",
"build:debug": "napi build"
}
}
```
Then you can require your native binding:
```js
require('./jarvis.node')
```
The `module_name` would be your `package` name in your `Cargo.toml`.
`xxx => ./xxx.node`
`xxx-yyy => ./xxx_yyy.node`
You can also copy `Dynamic lib` file to an appointed location:
```bash
napi build [--release] ./dll
napi build [--release] ./artifacts
```
There are [documents](./cli) which contains more details about the `@napi-rs/cli` usage.
## Testing
Because libraries that depend on this crate must be loaded into a Node executable in order to resolve symbols, all tests are written in JavaScript in the `test_module` subdirectory.
To run tests:
```sh
yarn build:test
yarn test
```
## Related projects
- [neon](https://www.neon-bindings.com)
- [node-bindgen](https://github.com/infinyon/node-bindgen)
## Features table
| Rust Type | Node Type | [NAPI Version](https://nodejs.org/api/n-api.html#n_api_node_api_version_matrix) | Minimal Node version | Enable by `napi` feature |
| ----------------------- | ---------------------- | ------------------------------------------------------------------------------- | -------------------- | ------------------------ |
| u32 | Number | 1 | v8.0.0 |
| i32/i64 | Number | 1 | v8.0.0 |
| f64 | Number | 1 | v8.0.0 |
| bool | Boolean | 1 | v8.0.0 |
| String/&'a str | String | 1 | v8.0.0 |
| Latin1String | String | 1 | v8.0.0 | latin1 |
| UTF16String | String | 1 | v8.0.0 |
| Object | Object | 1 | v8.0.0 |
| serde_json::Map | Object | 1 | v8.0.0 | serde-json |
| serde_json::Value | any | 1 | v8.0.0 | serde-json |
| Array | Array | 1 | v8.0.0 |
| Vec | Array | 1 | v8.0.0 |
| Buffer | Buffer | 1 | v8.0.0 |
| Null | null | 1 | v8.0.0 |
| Undefined/() | undefined | 1 | v8.0.0 |
| Result<()> | Error | 1 | v8.0.0 |
| T: Fn(...) -> Result | Function | 1 | v8.0.0 |
| Async/Future | Promise | 4 | v10.6.0 | async |
| Task (NOT YET) | Promise | 1 | v8.5.0 |
| (NOT YET) | global | 1 | v8.0.0 |
| (NOT YET) | Symbol | 1 | v8.0.0 |
| (NOT YET) | ArrayBuffer/TypedArray | 1 | v8.0.0 |
| (NOT YET) | threadsafe function | 4 | v10.6.0 | napi4 |
| (NOT YET) | BigInt | 6 | v10.7.0 | napi6 |