What is the role and purpose of Event Emitter in Node.js for event handling?

EventEmitter in Node.js is a class that implements the observer pattern. Its main role is to allow objects to generate events and subscribe to them, so they can react to these events asynchronously.

The purpose of EventEmitter is to simplify event handling, such as completion of an operation, data reception, errors, and others, without blocking the main thread. This is especially important in Node.js, where asynchrony and non-blocking I/O are key concepts.

Example of usage:

const EventEmitter = require('events');

class MyEmitter extends EventEmitter {}

const myEmitter = new MyEmitter();

// Subscribing to an event
myEmitter.on('event', () => {
  console.log('Event occurred!');
});

// Emitting an event
myEmitter.emit('event');

Thus, EventEmitter helps organize communication between parts of an application through events, making the code more modular and reactive.