nodeGO

A lightweight, custom JavaScript runtime built in Go using the Goja JS engine—designed to emulate core features of Node.js for learning and experimentation.

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🚀 Overview

nodeGO is a Node.js-inspired JavaScript runtime that mimics essential features such as synchronous file system access, timers, a CommonJS-style module system, and a minimal process object. It's designed to deepen understanding of JS runtimes, event loops, and native bindings by re-implementing these behaviors in Go.

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🧱 Architecture

• Goja VM: Executes JavaScript.
• Runtime Layer: Written in Go, exposes native APIs to JS.
• Core Bindings: Implemented natively (console, timers, fs, etc.).
• Module Loader: Loads and executes .js files via a custom require().

flowchart TD
    A[main.go] --> B[Initialize Goja VM]
    B --> C[Inject Native APIs]
    C --> D[Load entry JS file]
    D --> E[Execute via Goja]

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✅ Implemented Features

📦 Console

• console.log(msg)
• console.error(msg)
• console.warn(msg)

⏱️ Timers & Task Queues

• setTimeout(fn, delay)
• setInterval(fn, delay)
• setImmediate(fn)
• queueMicrotask(fn)
• process.nextTick(fn)

📁 File System (Sync)

• fs.readFileSync(path)
• fs.writeFileSync(path, data)

📦 Module System

• require(path) – supports .js files
• Loads and evaluates each module in isolated scope

🧠 Process Object

• process.cwd()
• process.argv
• process.env
• process.exit(code)

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📂 Project Structure

nodeGO/
├── main.go              # Entry point
├── runtime/
│   ├── runtime.go       # Core VM & event loop setup
│   ├── console.go       # console APIs
│   ├── timers.go        # Timers & task queues
│   ├── process.go       # process object
│   ├── module.go        # require() implementation
│   └── modules/
│       └── fs.go        # File system bindings

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🛠 Usage

1. Compile

go build -o nodego main.go

2. Run JavaScript File

./nodego examples/app.js arg1 arg2

3. Sample app.js

console.log('Running:', process.argv);
console.log('CWD:', process.cwd());
console.log('User:', process.env.USER);

const fs = require('./test.js');
fs.hello();

setTimeout(() => {
  console.log('Timeout triggered');
}, 1000);

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⚠️ Limitations

• No support for import/export (ESM)
• No asynchronous FS
• No HTTP or network APIs
• No built-in Buffer, path, crypto, etc.
• No npm support or module cache
• clearTimeout / clearInterval not implemented yet

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🛤️ Planned Features

• EventEmitter core implementation
• Stream API basics
• Simple HTTP server
• clearTimeout() and clearInterval()
• Module caching
• Global error handling (uncaughtException)
• CLI REPL

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Goal

This project is not intended to replace Node.js but to understand how it works internally by rebuilding its components from the ground up.