ES6 Class inheritance example

class-inheritance.js

class Person {
  constructor(name) {
    this.name = name;
  }

  dance() {
    return true;
  }
}

class Ninja extends Person {
  constructor(name, weapon) {
    super(name);
    this.weapon = weapon;
  }

  wieldWeapon() {
    return true;
  }
}

const person = new Person('Bob');

console.log(person instanceof Person, 'A person’s a person');
console.log(person.dance(), 'A person can dance.');
console.log(person.name === 'Bob', 'We can call it by name.');
console.log(!(person instanceof Ninja), 'But it’s not a Ninja');
console.log(typeof person.wieldWeapon === 'undefined', 'And it cannot wield a weapon');

const ninja = new Ninja('Yoshi', 'Wakizashi');

console.log(ninja instanceof Ninja, 'A ninja’s a ninja');
console.log(ninja.wieldWeapon(), 'That can wield a weapon');
console.log(ninja instanceof Person, 'But it’s also a person');
console.log(ninja.name === 'Yoshi', 'That has a name');
console.log(ninja.dance(), 'And enjoys dancing');