extend EventEmitter Example node.js

 We can inherit from event then our class can emit event here is example:

const EventEmitter = require('events')

class Tank extends EventEmitter {

FulledTill = 0

maxCapacity = 50

constructor(maxCapacity = 50) {

super()

this.maxCapacity = maxCapacity

}

addWater(addedAmount, listener) {

console.log("MaxCapacity",this.maxCapacity)

this.FulledTill = addedAmount + this.FulledTill

if (addedAmount + this.FulledTill > this.maxCapacity) {

this.emit("tankFull")

}

}

removeWater(removedAmount) {

console.log("MaxCapacity",this.maxCapacity)

this.FulledTill = this.FulledTill - removedAmount

if (this.FulledTill - removedAmount < 0) {

this.emit("tankEmpty")

}

}

}

function tankFullListener() {

console.log("Tank is Overflowing")

}

function tankEmptyListener() {

console.log("Tank is Empty")

}

var tank = new Tank(30)

tank.addListener("tankFull", tankFullListener)

tank.addListener("tankEmpty", tankEmptyListener)

tank.addWater(60)

tank.removeWater(60)

Output:

MaxCapacity 30

Tank is Overflowing

MaxCapacity 30

Tank is Empty