node-addon-api

What is node-addon-api?

The node-addon-api package is a helper library for building Node.js Addons in C++. It provides a C++ API that abstracts away the complexities of working with the low-level V8 and N-API provided by Node.js, making it easier to develop native addons.

What are node-addon-api's main functionalities?

Object Wrapping

Object wrapping allows C++ classes to be represented as JavaScript objects. It provides an easy way to create and manage objects that have a one-to-one relationship with C++ objects.

Napi::ObjectReference MyClass::constructor;

MyClass::MyClass(const Napi::CallbackInfo& info) : Napi::ObjectWrap<MyClass>(info) {
  // constructor implementation
}

Napi::Object MyClass::Init(Napi::Env env, Napi::Object exports) {
  Napi::HandleScope scope(env);

  Napi::Function func = DefineClass(env, "MyClass", {
    InstanceMethod("myMethod", &MyClass::MyMethod)
  });

  constructor = Napi::Persistent(func);
  constructor.SuppressDestruct();

  exports.Set("MyClass", func);
  return exports;
}

Function Arguments

The package provides a way to handle function arguments passed from JavaScript to C++ with type checking and conversion utilities.

Napi::Value MyFunction(const Napi::CallbackInfo& info) {
  Napi::Env env = info.Env();
  if (info.Length() < 2) {
    Napi::TypeError::New(env, "Expected at least two arguments").ThrowAsJavaScriptException();
  }

  Napi::String arg0 = info[0].As<Napi::String>();
  double arg1 = info[1].As<Napi::Number>().DoubleValue();

  // function implementation

  return Napi::String::New(env, "result");
}

Asynchronous Operations

node-addon-api provides utilities for performing asynchronous operations, allowing long-running tasks to be executed without blocking the Node.js event loop.

class MyAsyncWorker : public Napi::AsyncWorker {
public:
  MyAsyncWorker(Napi::Function& callback) : AsyncWorker(callback) {}

  void Execute() override {
    // Do work in another thread
  }

  void OnOK() override {
    Napi::HandleScope scope(Env());
    Callback().Call({Env().Null(), Napi::String::New(Env(), "Success")});
  }
};

Napi::Value RunAsyncWork(const Napi::CallbackInfo& info) {
  Napi::Function callback = info[0].As<Napi::Function>();
  MyAsyncWorker* worker = new MyAsyncWorker(callback);
  worker->Queue();
  return info.Env().Undefined();
}

Other packages similar to node-addon-api

nan

The 'nan' package is a header file filled with macros and utilities for making addon development for different versions of V8 easier. It predates N-API and node-addon-api, and while it's still used, node-addon-api is recommended for most cases due to its simpler API and direct support for N-API.

ffi-napi

The 'ffi-napi' package allows for calling foreign functions of dynamic libraries from Node.js. It is similar to node-addon-api in that it allows for native functionality in Node.js, but it focuses on interfacing with existing libraries rather than writing new native modules.

neon

The 'neon' package is a Rust framework for writing safe and fast native Node.js modules. Like node-addon-api, it simplifies the process of writing native addons but does so using Rust instead of C++.

README

node-addon-api module

This module contains header-only C++ wrapper classes which simplify the use of the C based Node-API provided by Node.js when using C++. It provides a C++ object model and exception handling semantics with low overhead.

• API References
• Badges
• Contributing
• License

API References

API references are available in the doc directory.

Current version: 8.2.2

(See CHANGELOG.md for complete Changelog)

node-addon-api is based on Node-API and supports using different Node-API versions. This allows addons built with it to run with Node.js versions which support the targeted Node-API version. However the node-addon-api support model is to support only the active LTS Node.js versions. This means that every year there will be a new major which drops support for the Node.js LTS version which has gone out of service.

The oldest Node.js version supported by the current version of node-addon-api is Node.js 18.x.

Badges

The use of badges is recommended to indicate the minimum version of Node-API required for the module. This helps to determine which Node.js major versions are supported. Addon maintainers can consult the Node-API support matrix to determine which Node.js versions provide a given Node-API version. The following badges are available:

Contributing

We love contributions from the community to node-addon-api! See CONTRIBUTING.md for more details on our philosophy around extending this module.

Team members

Active

Name	GitHub Link
Anna Henningsen	addaleax
Chengzhong Wu	legendecas
Jack Xia	JckXia
Kevin Eady	KevinEady
Michael Dawson	mhdawson
Nicola Del Gobbo	NickNaso
Vladimir Morozov	vmoroz

Emeritus

Emeritus

Name	GitHub Link
Arunesh Chandra	aruneshchandra
Benjamin Byholm	kkoopa
Gabriel Schulhof	gabrielschulhof
Hitesh Kanwathirtha	digitalinfinity
Jason Ginchereau	jasongin
Jim Schlight	jschlight
Sampson Gao	sampsongao
Taylor Woll	boingoing

License

Licensed under MIT

Changelog

8.2.2 (2024-11-07)

Bug Fixes

• mark external memory and version APIs as basic (#1597) (78da4fa)
• missing napi_delete_reference on ObjectWrap ref (#1607) (98aae33)