42 releases (13 stable)

1.4.0 Apr 1, 2021
1.3.4 Mar 31, 2021
1.2.0 Feb 26, 2021
1.0.0 Dec 29, 2020
0.1.0 Nov 30, 2017

#4 in FFI

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11,124 downloads per month
Used in rillrate-js

MIT license

210KB
6K SLoC

napi-rs

This project was initialized from xray

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

Platform Support

Lint Linux N-API@3 Linux musl macOS/Windows/Linux x64 Linux-aarch64 Linux-armv7 macOS-Android Windows i686 FreeBSD

Operating Systems

Linux macOS Windows MSVC FreeBSD

NodeJS

Node10 Node12 Node14 Node15

This library depends on N-API and requires Node@10.0.0 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/JavaScript 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(always)]
fn fibonacci_native(n: i64) -> i64 {
  match n {
    1 | 2 => 1,
    _ => fibonacci_native(n - 1) + fibonacci_native(n - 2),
  }
}

Register module

#[macro_use]
extern crate napi_derive;

use napi::{JsObject, Result};

/// `exports` is `module.exports` object in NodeJS
#[module_exports]
fn init(mut exports: JsObject) -> Result<()> {
  exports.create_named_method("fibonacci", fibonacci)?;
  Ok(())
}

And you can also create JavaScript value while registering module:

#[macro_use]
extern crate napi_derive;

use napi::{JsObject, Result, Env};

#[module_exports]
fn init(mut exports: JsObject, env: Env) -> Result<()> {
  exports.create_named_method("fibonacci", fibonacci)?;
  exports.set_named_property("DEFAULT_VALUE", env.create_int64(100)?)?;
  Ok(())
}

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.

[package]
name = "awesome"

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

[dependencies]
napi = "1.0"
napi-derive = "1.0"

[build-dependencies]
napi-build = "1.0"

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 Windows x64 MSVC and FreeBSD.

See the included test_module for an example add-on.

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.

{
  "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:

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:

napi build [--release] ./dll
napi build [--release] ./artifacts

There are documents 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:

yarn build:test
yarn test

Features table

Create JavaScript values

NAPI NAPI Version Minimal Node version Status
napi_create_array 1 v8.0.0
napi_create_array_with_length 1 v8.0.0
napi_create_arraybuffer 1 v8.0.0
napi_create_buffer 1 v8.0.0
napi_create_buffer_copy 1 v8.0.0
napi_create_date 5 v11.11.0
napi_create_external 1 v8.0.0
napi_create_external_arraybuffer 1 v8.0.0
napi_create_external_buffer 1 v8.0.0
napi_create_object 1 v8.0.0
napi_create_symbol 1 v8.0.0
napi_create_typedarray 1 v8.0.0
napi_create_dataview 1 v8.3.0
napi_create_int32 1 v8.4.0
napi_create_uint32 1 v8.4.0
napi_create_int64 1 v8.4.0
napi_create_double 1 v8.4.0
napi_create_bigint_int64 6 v10.7.0
napi_create_bigint_uint64 6 v10.7.0
napi_create_bigint_words 6 v10.7.0
napi_create_string_latin1 1 v8.0.0
napi_create_string_utf16 1 v8.0.0
napi_create_string_utf8 1 v8.0.0

Functions to convert from N-API to C types

NAPI NAPI Version Minimal Node Version Status
napi_get_array_length 1 v8.0.0
napi_get_arraybuffer_info 1 v8.0.0
napi_get_buffer_info 1 v8.0.0
napi_get_prototype 1 v8.0.0
napi_get_typedarray_info 1 v8.0.0
napi_get_dataview_info 1 v8.3.0
napi_get_date_value 5 v11.11.0
napi_get_value_bool 1 v8.0.0
napi_get_value_double 1 v8.0.0
napi_get_value_bigint_int64 6 v10.7.0
napi_get_value_bigint_uint64 6 v10.7.0
napi_get_value_bigint_words 6 v10.7.0
napi_get_value_external 1 v8.0.0
napi_get_value_int32 1 v8.0.0
napi_get_value_int64 1 v8.0.0
napi_get_value_string_latin1 1 v8.0.0
napi_get_value_string_utf8 1 v8.0.0
napi_get_value_string_utf16 1 v8.0.0
napi_get_value_uint32 1 v8.0.0
napi_get_boolean 1 v8.0.0
napi_get_global 1 v8.0.0
napi_get_null 1 v8.0.0
napi_get_undefined 1 v8.0.0

Working with JavaScript Values and Abstract Operations

NAPI NAPI Version Minimal Node Version Status
napi_coerce_to_bool 1 v8.0.0
napi_coerce_to_number 1 v8.0.0
napi_coerce_to_object 1 v8.0.0
napi_coerce_to_string 1 v8.0.0
napi_typeof 1 v8.0.0
napi_instanceof 1 v8.0.0
napi_is_array 1 v8.0.0
napi_is_arraybuffer 1 v8.0.0
napi_is_buffer 1 v8.0.0
napi_is_date 1 v8.0.0
napi_is_error 1 v8.0.0
napi_is_typedarray 1 v8.0.0
napi_is_dataview 1 v8.3.0
napi_strict_equals 1 v8.0.0
napi_detach_arraybuffer 7 v13.3.0
napi_is_detached_arraybuffer 7 v13.3.0

Dependencies

~0–1.6MB
~45K SLoC