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