napi-rs v0.3.10

napi-rs

This project was initialized from xray

A minimal library for building compiled NodeJS add-ons in Rust.

Platform Support

Operating Systems

NodeJS

This library depends on N-API and requires Node@8.9 or later.

We already have some packages written by napi-rs: node-rs

One nice feature is that this crate allows you to build add-ons purely with the Rust toolchain and without involving node-gyp.

Taste

You can start from package-template to play with napi-rs

Define JavaScript functions

#[js_function(1)] // ------> arguments length, omit for zero
fn fibonacci(ctx: CallContext) -> Result<JsNumber> {
  let n = ctx.get::<JsNumber>(0)?.try_into()?;
  ctx.env.create_int64(fibonacci_native(n))
}

#[inline]
fn fibonacci_native(n: i64) -> i64 {
  match n {
    1 | 2 => 1,
    _ => fibonacci_native(n - 1) + fibonacci_native(n - 2),
  }
}

Register module

/// test_module is Module name
register_module!(test_module, init);

/// Module is `module` object in NodeJS
fn init(module: &mut Module) -> Result<()> {
  module.create_named_method("fibonacci", fibonacci)?;
}

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.

[lib]
crate-type = ["cdylib"]

[dependencies]
napi = "0.5"
napi-derive = "0.5"

[build-dependencies]
napi-build = "0.2"

And create build.rs in your own project:

// build.rs
extern crate napi_build;

fn main() {
  napi_build::setup();
}

So far, the napi build script has only been tested on macOS Linux and Windows x64 MSVC.

See the included test_module for an example add-on.

Run cargo build to produce the Dynamic lib file. And install the napi-rs to help you copy Dynamic lib file to .node file in case you can require it in your program.

{
  "package": "your pkg",
  "devDependencies": {
    "napi-rs": "latest"
  },
  "scripts": {
    "build": "cargo build && napi build",
    "build-release": "cargo build --release && napi build --release"
  }
}

Then you can require your native binding:

require('./target/debug|release/[module_name].node')

The module_name would be your package name in your Cargo.toml.

xxx => ./target/debug|release/xxx.node

xxx-yyy => ./target/debug|release/xxx_yyy.node

You can also copy Dynamic lib file to an appointed location:

napi build [--release] .
napi build [--release] ./mylib

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:

yarn build:test
yarn test

Features table

Create JavaScript values

Functions to convert from N-API to C types

Working with JavaScript Values and Abstract Operations