README.md

Node.js N-API for Rust! [work in progress]

High-level N-API bindings for Node.js addons written in Rust.

Warning: this is a proof-of-concept implementation that's not intended for use yet. The project is under initial phase of development, the API is a quite sketchy and is going to be refactored heavily. If you are interested in contributing, though, it is super welcome!

The project is covered by a Code of Conduct.

Crates

• napi-sys: low-level bindings to N-API generated from node_api.h using bindgen.
• napi: high-level and rusty wrappers around napi-sys.
• napi-derive: contains a procedural macro that allows to construct typesafe structures that represent N-API callback parameters and automatically validate the arguments that JavaScript code passes in.

Example

Check out the example directory to see the full source code and project structure of this example. (TODO: initialize the module from Rust too).

lib.rs

#[macro_use]
extern crate napi;
#[macro_use]
extern crate napi_derive;

use napi::{NapiEnv, NapiNumber, NapiResult, NapiUndefined};

#[derive(NapiArgs)]
struct HelloArgs;

fn hello<'a>(env: &'a NapiEnv, _: &HelloArgs) -> NapiResult<NapiUndefined<'a>> {
    println!("Hello from the Rust land!");
    NapiUndefined::new(env)
}

#[derive(NapiArgs)]
struct AddArgs<'a> {
    first: NapiNumber<'a>,
    second: NapiNumber<'a>,
}

fn add<'a>(env: &'a NapiEnv, args: &AddArgs<'a>) -> NapiResult<NapiNumber<'a>> {
    let first = args.first.to_i32()?;
    let second = args.second.to_i32()?;
    NapiNumber::from_i32(env, first + second)
}

napi_callback!(example_hello, hello);
napi_callback!(example_add, add);

example.js

'use strict';

const addon = require('./build/Release/example.node');

addon.hello();
console.log(addon.add(1, 2));