How I learned from a crazy idea / The ES6 way

by Arnaud Buchholz

HTML

<script src="https://arnaudbuchholz.github.io/blog/jsfiddle-assert.js"></script>

JavaScript

class Es6A {
  constructor () {
    this._a = "A";
  }

  a () {
    return this._a;
  }
}

class Es6B extends Es6A {
  constructor () {
    super();
    this._b = "B";
  }

  b () {
    return this._b;
  }
}

var b = new Es6B();
assert(() => b instanceof Es6A);
assert(() => b.a() === "A");
assert(() => b instanceof Es6B);
assert(() => b.b() === "B");