👋 there!

ES4X is a JavaScript runtime that runs on top of GraalVM and used Eclipse Vert.x for high performance IO and event loop.

# add es4x-pm globally
npm install -g es4x-pm

# create a generic project
mkdir my-app
cd my-app
# init the project
es4x init
# add other dependencies
npm install @vertx/unit --save-dev
npm install @vertx/core --save-prod
# will trigger the download
# of the java dependencies
npm install

/// <reference types="es4x" />
// @ts
-check
vertx
  .createHttpServer()
  .requestHandler(function (req) {
    req.response().end("Hello!");
  })
  .listen(8080);
console.log('Server listening at: http://localhost:8080/');

import { TestSuite } from '@vertx/unit';
const suite = TestSuite.create(

The project started a while ago as an attempt to modernize the polyglot aspect of vert.x.

The goals of the project are simple:

1. Provide a node-like developer experience
2. Expose all APIs as .d.ts files
3. K.I.S.S.

As the project has been through experimentation for a long time, there are many undocumented features that need ♥.

It can also be an intesting starting point if you would like to learn more about GraalVM, by reading the code, fixing bugs, or add more tests!

Contributors Wanted

If you're interested in practise your Java and JavaScript skills, follow the project link and see the issues tagged as Hacktoberfest. If you would like to work on other features, please open an issue and we will gladly review it and tag if necessary!