# napi-rs
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> This project was initialized from [xray](https://github.com/atom/xray)
A minimal library for building compiled `Node.js` add-ons in `Rust`.
<p>
<a href="https://docs.rs/crate/napi"><img src="https://docs.rs/napi/badge.svg"></img></a>
<a href="https://crates.io/crates/napi"><img src="https://img.shields.io/crates/v/napi.svg"></img></a>
<a href="https://www.npmjs.com/package/@napi-rs/cli"><img src="https://img.shields.io/npm/v/@napi-rs/cli.svg"></img></a>
</p>
## Ecosystem
<p align="center">
<a href="https://www.prisma.io/" target="_blank">
<img alt="Prisma" src="https://raw.githubusercontent.com/napi-rs/napi-rs/main/images/prisma.svg" height="50px">
</a>
<a href="https://swc.rs/" target="_blank">
<img alt="swc" src="https://raw.githubusercontent.com/swc-project/logo/master/swc.png" height="50px">
</a>
<a href="https://parceljs.org/" target="_blank">
<img alt="Parcel" src="https://user-images.githubusercontent.com/19409/31321658-f6aed0f2-ac3d-11e7-8100-1587e676e0ec.png" height="50px">
</a>
<a href="https://nextjs.org/">
<img alt="next.js" src="https://assets.vercel.com/image/upload/v1607554385/repositories/next-js/next-logo.png" height="50px">
<img alt="nextjs.svg" src="https://raw.githubusercontent.com/napi-rs/napi-rs/main/images/nextjs.svg" height="50px">
</a>
</p>
## Platform Support
[](https://github.com/napi-rs/napi-rs/actions/workflows/android-armv7.yml)
[](https://github.com/napi-rs/napi-rs/actions/workflows/windows-arm.yml)
[](https://cirrus-ci.com/github/napi-rs/napi-rs?branch=main)
## MSRV
**Rust** `1.57.0`
| 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 | ✓ | ✓ | ✓ | ✓ |
| Linux armv7 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
/// import the preludes
use napi::bindgen_prelude::*;
use napi_derive::napi;
/// module registration 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<T: Fn(String) -> 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<T>(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<Buffer> {
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
| 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<any> | 1 | v8.0.0 |
| Vec<T> | Array<T> | 1 | v8.0.0 |
| Buffer | Buffer | 1 | v8.0.0 |
| External<T> | External<T> | 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<T> | Function | 1 | v8.0.0 |
| Async/Future | Promise<T> | 4 | v10.6.0 | async |
| AsyncTask | Promise<T> | 1 | v8.5.0 |
| JsGlobal | global | 1 | v8.0.0 |
| JsSymbol | Symbol | 1 | v8.0.0 |
| Int8Array/Uint8Array ... | TypedArray | 1 | v8.0.0 |
| JsFunction | threadsafe function | 4 | v10.6.0 | napi4 |
| BigInt | BigInt | 6 | v10.7.0 | napi6 |