How to use Event Emitter

event-emitter-usage.js

'use strict'

const { EventEmitter } = require('events')

function print(evt) {
  console.log('#####')
  console.log('Event: ', evt.name)
  if (evt.data) {
    console.log(evt.data)
  }
  console.log('#####')
}

const ee = new EventEmitter()

ee.on('start', print)
ee.on('data', print)
ee.on('end', print)

ee.emit('start', { name: 'start' })
ee.emit('data', { name: 'data', data: 'EVENT DATA ...' })
ee.emit('end', { name: 'end'})