Gojo

A JavaScript runtime built with Go, powered by goja.

Overview

Gojo is a lightweight JavaScript runtime that allows you to execute JavaScript code using Go. It implements an event loop with support for asynchronous operations like setTimeout and setInterval, making it suitable for running Node.js-style JavaScript code.

Features

• JavaScript Execution: Run JavaScript files with ES6+ syntax support
• Event Loop: Full implementation of event loop for asynchronous operations
• Timer APIs: Support for setTimeout, setInterval, clearTimeout, and clearInterval
• Console API: Built-in console.log for output
• Process API: Access to command-line arguments via process.argv and process.exit()

Installation

go get github.com/nomad-pixel/gojo

Usage

Running a JavaScript file

go run cmd/gojo/main.go <path-to-js-file>

Example

Create a JavaScript file examples/hello.js:

console.log("start");

setTimeout(() => {
  console.log("timeout 1 (100ms)");
}, 100);

const a = ()  => {
  console.log("timeout 2 (50ms)");
}

let count = 0;
const id = setInterval(() => {
  console.log("interval tick", ++count);
  if (count >= 3) {
    console.log("clearInterval");
    clearInterval(id);
  }
}, 200);

a();

console.log("end");

Run it:

go run cmd/gojo/main.go examples/hello.js

API Reference

Global Objects

console

• console.log(...args) - Print values to stdout

process

• process.argv - Array of command-line arguments
• process.exit(code) - Exit the process with the specified code

Timer Functions

• setTimeout(callback, delay) - Execute callback after delay in milliseconds
• setInterval(callback, delay) - Execute callback repeatedly with delay between executions
• clearTimeout(id) - Cancel a timeout
• clearInterval(id) - Cancel an interval

Architecture

Gojo is built with the following components:

• Runtime (internal/runtime/runtime.go) - Main runtime that initializes the VM and global APIs
• Event Loop (internal/runtime/loop.go) - Implements the event loop and timer management
• CLI (cmd/gojo/main.go) - Command-line interface for running JavaScript files

Requirements

• Go 1.22.6 or higher

License

MIT