mini-emit

📣 A minimal and strongly typed event emitter with no dependencies — just ~500 bytes gzipped!

This library reuses and extracts parts of the core implementation from mini-i18n. The original logic was refined and optimized for a standalone event emitter.

✨ Features

• ✅ Type-safe event definitions
• 📦 Zero dependencies and ultra-lightweight
• 🧠 Simple API: on, off, once, emit, clear
• 🧩 Can be used in both browser and Node.js environments
• ⚙️ Ideal for internal module-level event handling

📦 Installation

Using npm:

npm install mini-emit

Using CDN:

<script src="https://cdn.jsdelivr.net/npm/mini-emit"></script>
<!-- or -->
<script src="https://unpkg.com/mini-emit"></script>

<script>
  const emitter = new miniemit.EventEmitter()
</script>

🚀 Usage Example

import { EventEmitter } from 'mini-emit'

interface Events {
  ready: void
  message: string
  data: { id: number, name: string }
}

const emitter = new EventEmitter<Events>()

// Subscribe to events
const stop = emitter.on('message', (msg) => {
  console.log('Got message:', msg)
})

// Emit events
emitter.emit('ready')
emitter.emit('message', 'Hello world')
emitter.emit('data', { id: 1, name: 'Lete' })

// One-time listener
emitter.once('ready', () => {
  console.log('Only once!')
})

// Remove listener
stop()

// Clear all listeners
emitter.clear()

// Clear specific event listeners
emitter.clear('message')

🧩 API

new EventEmitter<T>()

Create a new event emitter instance with optional event type map.

on(event, listener): () => void

Add a listener to the specified event.

const off = emitter.on('eventName', (payload) => {})
off() // Cancel the listener

once(event, listener): () => void

Listen to an event only once.

emitter.once('eventName', (payload) => {
  console.log('Triggered only once')
})

off(event, listener): void

Remove a specific listener.

emitter.off('eventName', listener)

emit(event, payload?): void

Emit an event with optional payload.

emitter.emit('eventName', data)

clear(event?): void

Clear all listeners or only listeners for a specific event.

emitter.clear() // Clear all
emitter.clear('eventName') // Clear specific

🔧 Type Safety

With TypeScript, you can provide an EventMap type to get full type checking on event names and payloads.

interface EventMap {
  login: { userId: string }
  logout: void
}

const emitter = new EventEmitter<EventMap>()

emitter.emit('login', { userId: 'abc123' }) // ✅ OK
emitter.emit('logout') // ✅ OK
emitter.emit('logout', 'unexpected') // ❌ Type error

📄 License

MIT License © Lete114