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this duktape binding project will be discontinued. a quickjs binding version is under development, it supports more modern javascript features. unity-jsb


Build Status


Integerate duktape (an embedded javascript engine) into unity, you can load and run javascript at runtime.
Typescript is a preferred choice, it provides type checks.

editing script


  • nodejs-like module or browser-like singular js depends on you
  • generate C# to js type binding code, and coresponding d.ts type definition files
  • setTimeout/setInterval/clearTimeout/clearInterval compatible
  • c# delegates
  • optimized unity common valuetypes (Vector2/3,Quaternion,Color...)
  • fixed-point math support (libfixmath)
  • websocket (libwebsockets)
  • iOS (64bit, bitcode)
  • Android (v7a, v8a, x86)
  • remote debugger (vscode)
  • promise (bluebird.js)
  • coroutine (duktape thread)
  • socket (tcp/udp)
  • kcp (not implemented)

You can use lots of pure js libraries in your project, such as protobufjs. protobufjs

Type definition files

The generated d.ts files will improve auto-complete. It will give the information of exposed types from C# and C.

  • delegate type information type definition files
  • generic constraints for out/ref parameter type definition files
  • friendly interface for AddComponent/GetComponent type definition files


If you use typescript, install typescript at first

npm install -g typescript


# --depth=1 is highly recommended
git clone --depth=1


prebuilt libraries already in /prebuilt/debug and /prebuilt/release directories.

python/pip/pyyaml is prerequisites.

pip install pyyaml

duktape original source code is at /duktape-/src-input

./configure_duktape.bat # combined duktape source code will be generated 
# at:
# /build/src-debug (with debugger)
# /build/src-release (without debugger)
./make_duktape_<platform>.bat # or ./make_duktape_<platform>.sh in osx

if you build duktape for android in windows, run make_duktape_android.bat in visual studio cross tools commandline (e.g VS2015 x64 ARM Cross Tools Command Prompt).

'./scratch' is a playground for duktape testing in a simple command line app.


Sample code

// if your tsconfig.json defined {"module": "commonjs"}, you can 'import' modules like node-js. 

// import module
import { B } from "base/b"
// import module with relative path (. or ..)
import { C } from "./base/c"

class MyPlayer {
    Start() {

    // Update() {
    // }

    Jump() {

export class A {
    private go: GameObject
    constructor () {
        this.go = new GameObject("test go")
        this.go.transform.localPosition = new Vector3(1, 2, 3) 
        // use Bridge to receive Enable/Disable/Update 
        // don't use the approach a lot, it's better to dispatch futher logic in a single Bridge
        this.go.AddComponent(DuktapeJS.Bridge).SetBridge(new MyPlayer()) 

        let f = new Custom()
        // you can assign function to c# delegate
        f.onopen = function () {
            // ...
        // if you want to register multiple listener, use DuktapeJS.Dispather 
        // you can also use typed Dispatcher generated in _DuktapeDelegates.d.ts, it provides type checks
        f.onload = new DuktapeJS.Dispatcher1<void, string>() 
        f.onload.on(this, this.onload)  // add listener, this.onload) // remove listener              // clear all listeners of this
        f.onload.clear()                // clear all

        // 'out' parameter in c#
        let v = {}
        if (System.Int32.TryParse("123", v)) {

    private onload(ev: string) {
        let timer1 = setInterval(() => {
        }, 1000)

        setTimeout((a, b) => {
            console.log("timeout", a, b)
        }, 5000, "Arg1", 123)

    square() {

// websocket
let ws = DuktapeJS.WebSocket()
ws.on("open", () => {
    setInterval(() => {
        ws.send("hello, world") // string or buffer 
    }, 1000)
ws.on("data", data => {
    console.log("ws receive data", data) // string or buffer (depends on websocket message type you use)
ws.on("close", () => {
    console.log("connection lost")
setInterval(() => {
}, 50)
// http request example
console.log("http requesting...");
HttpRequest.GET("", null, (status, res) => {
    console.warn("http response:", status, res);
    if (status) {
        let obj = JSON.parse(res);
        console.log("as object", obj.message);
// coroutine example
let co = new Coroutine(function (x) {
    console.log("duktape thread, start:", x);
    for (var i = 1; i <= 5; ++i) {
        let r = Coroutine.yield(i);
        console.log("duktape thread, yield:", r);
    // Coroutine.break();
    return "all done!";
let c = 'A'.charCodeAt(0);
while ( {
    console.log("duktape thread, next:", co.value);
console.log("duktape thread, done:", co.value);

Dev status

It's not stable enough, do not use it in production environment.
Vector2/Matrix3x3/Matrix4x4/Quaternion valuetypes optimization is partially written in c, and not fully tested.


Execute menu item [Duktape -> Generate Bindings] to generate binding code. Typescript source files will be compiled into js after your modification and switch back to Unity Editor.

How to customize exported types

  • duktape.json modify the basic configuration at ./duktape.json (details in Assets/Duktape/Editor/Prefs.cs)
    "outDir": "Assets/Generated",
    "typescriptDir": "Assets/Generated",
    "extraExt": "",
    // rootpath of ts/js project
    "workspace": "",
    "logPath": "Temp/duktape.log",
    // auto, cr, lf, crlf
    "newLineStyle": "auto",
    "implicitAssemblies": [
    "explicitAssemblies": [
    // types in blacklist will not be exported
    "typePrefixBlacklist": [
        // more types ...
    "ns": "DuktapeJS",
    "tab": "    "
  • implements Duktape.IBindingProcess interface or extends AbstractBindingProcess class
public class MyCustomBinding : AbstractBindingProcess
    public override void OnPreCollectTypes(BindingManager bindingManager)
            .SetMethodBlocked("AMethodNameWithParameters", typeof(string), typeof(int))

    public override void OnCleanup(BindingManager bindingManager)
        Debug.Log($"finish @ {DateTime.Now}");

Sample scene

Assets/Scenes/main.unity (Sample.cs) demonstrate the basic usage.


Support js/ts remote debug.

the libraries in unity project is built with debugger support. if you want to use a release version without debugger support, checkout /prebuilt/release. or compile them by yourself.


Name: Duktape Debugger
Id: haroldbrenes.duk-debug
Description: Debug Adapter for Duktape runtimes.
Version: 0.5.6
Publisher: HaroldBrenes
VS Marketplace Link:

If you are debugging ts sources, this extension has some path-resolve issues break the debug process, you can try the modified version.

Referenced libraries