EmittEvent

A high-performance, lightweight EventEmitter for modern JavaScript environments, strictly modeled after the Node.js EventEmitter API.

Features

• Lightweight: Zero dependencies, minimal footprint.
• Node.js Compatible: Implements the core EventEmitter methods.
• Performant: Optimized internal storage using Object.create(null) to avoid prototype overhead.
• TypeScript Support: Full type definitions included.

Installation

npm install emittevent

Usage

import EventEmitter from 'emittevent';

const em = new EventEmitter();

em.on('hello', (name) => {
  console.log(`Hello, ${name}!`);
});

em.emit('hello', 'World'); // "Hello, World!"

API Documentation

on(eventName, listener) / addListener(eventName, listener)

Adds the listener function to the end of the listeners array for the event named eventName.

once(eventName, listener)

Adds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked.

emit(eventName, ...args)

Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.

• Returns: true if the event had listeners, false otherwise.

removeListener(eventName, listener) / off(eventName, listener)

Removes the specified listener from the listener array for the event named eventName.

removeAllListeners([eventName])

Removes all listeners, or those of the specified eventName.

eventNames()

Returns an array listing the events for which the emitter has registered listeners.

listeners(eventName)

Returns a copy of the array of listeners for the event named eventName.

listenerCount(eventName)

Returns the number of listeners listening to the event named eventName.

License

MIT