What is Event Emmitter?
EventEmitter class lies in events module. It is accessibly via following syntax:
//import events module var events = require('events'); //create an eventEmitter object var eventEmitter = new events.EventEmitter();
When an EventEmitter instance faces any error, it emits an 'error' event. When new listener is added, 'newListener' event is fired and when a listener is removed, 'removeListener' event is fired.
EventEmitter provides multiple properties like on and emit. on property is used to bind a function with the event and emit is used to fire an event.