Testing Super

Not your fiddle

by Sudoku Lovor

Babel + JSX

class Human {
  constructor(token, name, age) {
    this.token = token;
    this.name = name;
    this.age = age;
  }
}

class Child extends Human {
  constructor(token, name, age, likesMilk) {
    super(age);
    this.likesMilk = likesMilk;
  }
}

const marko = new Human(1, 'marko');
const ivana = new Child(121, 'Ivana', 2, false);

var el = document.createElement('pre');

var obj = {marko, ivana}
el.innerHTML = JSON.stringify(obj, null, 2)
document.body.appendChild(el);