example of work with 'class' keyword in JS

classExample.js

class Mammal {
  constructor(sound) {
    this._sound = sound;
  }
   talk() {
     return this._sound;
   }
}

  class Dog extends Mammal {
    constructor() {         /*super will bound to constructor in Mammal */
      super('Woofelifffffffffeeee')
    }
  }


let Artur = new Mammal('Super-WOof');
let poof =  Artur.talk()
console.log(poof);

let Dogie = new Dog();
let shmoof =  Dogie.talk()
console.log(shmoof);

Dogie._sound = 'meow';
let newShmoof = Dog.prototype.talk.bind({
  _sound: 'Opppa'
})()
console.log(newShmoof);

let prototypeCheck = Dog.prototype.isPrototypeOf(Dogie); // true
let prototypeCheck2 = Dog.prototype.isPrototypeOf(Artur); // false
console.log(prototypeCheck);