Tutorial by Examples

In the HTTP server code (e.g. server.js): const EventEmitter = require('events') const serverEvents = new EventEmitter() // Set up an HTTP server const http = require('http') const httpServer = http.createServer((request, response) => { // Handler the request... // Then emit an event...

Event Emitters are built into Node, and are for pub-sub, a pattern where a publisher will emit events, which subscribers can listen and react to. In Node jargon, publishers are called Event Emitters, and they emit events, while subscribers are called listeners, and they react to the events. // Requ...

The function EventEmitter.eventNames() will return an array containing the names of the events currently subscribed to. const EventEmitter = require("events"); class MyEmitter extends EventEmitter{} var emitter = new MyEmitter(); emitter .on("message", function(){ //list...

The function Emitter.listenerCount(eventName) will return the number of listeners that are currently listening for the event provided as argument const EventEmitter = require("events"); class MyEmitter extends EventEmitter{} var emitter = new MyEmitter(); emitter .on("data&quot...