Node Event Module

Node has a concept of event-driven programming, in which code is written to react rather than be called.

Node has an inbuilt event module about which you learn in-depth from here, we will use event listener and event emitter method of this class.

const EventEmitter = require('events');

const event = new EventEmitter();

Event Listener

An event listener is a logic which will be executed when an event is emitted. Make sure you have declared Event listener before emitting the event.

event.on('some-event', function() {
  // some logic
});


//es6
event.on('some-event', () => {
  // some logic
});


//with parameter
event.on('some-event', (parameter) => {
  // some logic
});

Event Emitter

Event emitter is used to trigger a specific event listener.

event.emit('some-event', parameter);