@nowarajs/typed-event-emitter

🎯 TypedEventEmitter

📌 Table of Contents

🎯 TypedEventEmitter

📝 Description

A TypeScript library that provides a strongly typed event emitter for type-safe event handling.

TypedEventEmitter extends EventEmitter with full TypeScript support, allowing developers to define custom events with specific payloads while ensuring complete type safety and reducing runtime errors in event-driven applications.

✨ Features

🔒 Type Safety: Full TypeScript support with strongly typed event names and payloads
🧩 Generic Design: Define custom event maps for your specific use cases
🔄 Familiar API: Extends Node.js EventEmitter with the same familiar methods
📦 Zero Dependencies: No external runtime dependencies
🚀 Modern: Built with modern TypeScript and supports ESM
🧪 Well Tested: Comprehensive test suite included

🔧 Installation

bun add @nowarajs/typed-event-emitter

⚙️ Usage

Basic Usage

import { TypedEventEmitter } from '@nowarajs/typed-event-emitter';

// Define your event map
interface MyEvents {
  userLogin: [{ userId: string; timestamp: Date }];
  userLogout: [{ userId: string }];
  dataUpdate: [{ id: number; data: any }];
  error: [Error];
}

// Create a typed event emitter
const emitter = new TypedEventEmitter<MyEvents>();

// Type-safe event listening
emitter.on('userLogin', (payload) => {
  // payload is automatically typed as { userId: string; timestamp: Date }
  console.log(`User ${payload.userId} logged in at ${payload.timestamp}`);
});

// Type-safe event emission
emitter.emit('userLogin', { 
  userId: 'user123', 
  timestamp: new Date() 
});

Advanced Usage

import { TypedEventEmitter } from '@nowarajs/typed-event-emitter';

// Multiple parameters
interface Events {
  move: [x: number, y: number];
  click: [button: 'left' | 'right', x: number, y: number];
  keypress: [key: string, modifiers: string[]];
}

const input = new TypedEventEmitter<Events>();

// Multiple parameters are fully typed
input.on('move', (x, y) => {
  console.log(`Mouse moved to ${x}, ${y}`);
});

input.on('click', (button, x, y) => {
  console.log(`${button} click at ${x}, ${y}`);
});

// Emit with multiple arguments
input.emit('move', 100, 200);
input.emit('click', 'left', 50, 75);

📚 API Reference

You can find the complete API reference documentation for TypedEventEmitter at:

Reference Documentation

⚖️ License

Distributed under the MIT License. See LICENSE for more information.

📧 Contact

NowaraJS - GitHub Organization

Project Link