matchlet

A TypeScript implementation of PHP-like pattern matching with type safety and additional features.

Why I Created This

I've always loved PHP's match expression and have been using my own TypeScript implementation of it for years in various projects. Recently, I wanted to enhance it with a PHP-style _default key functionality. After consulting with Claude AI about the implementation, the result turned out so well that I decided to make it my first open-source contribution.

This is my first open-source project, and I'm excited to share it with the community.

Installation

npm install matchlet

Usage

import { match } from 'matchlet';

// Basic usage with default value
const result1 = match('a', {
    a: 'value1',
    b: 'value2',
    _default: 'default value'
});

// Using with functions
const result2 = match('x', {
    a: () => 'value1',
    _default: () => 'not found'
});

// Without default (all keys required)
const result3 = match('a', {
    a: 'value1',
    b: 'value2'
});

// With specific types
interface User {
    name: string;
    age: number;
}

const userResult = match<string, User>('admin', {
    admin: { name: 'Admin', age: 30 },
    guest: { name: 'Guest', age: 0 },
    _default: { name: 'Unknown', age: -1 }
});

Features

• TypeScript type safety
• PHP-like pattern matching
• Support for both values and functions
• Optional default values with _default key
• Generic type support

Type Safety

The library provides compile-time type checking:

• When using _default, other keys are optional
• Without _default, all keys are required
• Supports both direct values and functions
• Generic types for flexible usage

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.