🛠️ Unify-JS — Minimal JavaScript Type Checker

Unify-JS is a lightweight, experimental type checker for JavaScript that catches type mismatches before runtime 🚀. It works directly with plain JS code — no TypeScript setup required.

✨ Features

• 🔍 Detects type mismatches in variables, function calls, and expressions
• 🧠 Supports polymorphic functions (adaptable to multiple types)
• 📦 Zero configuration — install and run
• 💡 Clear CLI output for faster debugging

📦 Installation

npm install --save-dev @hareesh108/unify-js

⚡ Quick Start

1. Create your program:

// myProgram.js
const double = (x) => { return x + x; };
const num = 5;
const str = "hello";

const doubledNum = double(num);
const mixed = double(num) + double(str); // ❌ Type error

2. Add to package.json:

{
  "scripts": {
    "typecheck": "unify-js myProgram.js"
  }
}

3. Run:

npm run typecheck

🖥 Example Output

❌ Type mismatch in binary operation: cannot add Number to String

🧪 More Examples

✅ No type errors:

const identity = (x) => { return x; };
const result = identity(42);

❌ Type mismatch:

const add1 = (x) => { return x + 1; };
const res = add1("hello"); // Error

🛠 How It Works

• compile → Parses JavaScript into an AST
• typeCheck → Infers and validates types
• nameCheck → Checks naming and scope rules

📋 Roadmap

• 🌐 Enhanced CLI output with code highlighting
• 🧩 Plugin system for custom rules
• 🖍 VS Code integration

📜 License

MIT © 2025 Hareesh Bhittam