Events in NodeJS

Introduction

Node.js is an asynchronous event-driven architecture
All objects that emit events are instances of the EventEmitter class
Event names are camel-cased strings
When the EventEmitter object emits an event, functions attached to that specific event are called synchronously

Implement event

eventEmitter.on() method is used to register listeners
eventEmitter.emit() method is used to trigger the event

const EventEmitter = require('events');
class ShopEmitter extends EventEmitter { }
const cartEmitter = new ShopEmitter();
cartEmitter.on('addItem', function (params) {
    console.log('Item added to cart');
});
let params = { id: 1 };
cartEmitter.emit('addItem', params);
// output
// Item added to cart