javascript prototype inheritance example

function Animal (name, energy) {
  this.name = name
  this.energy = energy
}

Animal.prototype.eat = function (amount) {
  console.log(`${this.name} is eating.`)
  this.energy += amount
}

Animal.prototype.sleep = function (length) {
  console.log(`${this.name} is sleeping.`)
  this.energy += length
}

Animal.prototype.play = function (length) {
  console.log(`${this.name} is playing.`)
  this.energy -= length
}

function Dog (name, energy, breed) {
  Animal.call(this, name, energy)

  this.breed = breed
}

Dog.prototype = Object.create(Animal.prototype)

Dog.prototype.bark = function () {
  console.log('Woof Woof!')
  this.energy -= .1
}

const charlie = new Dog('Charlie', 10, 'Goldendoodle')
console.log(charlie.constructor)