Get superclass name in ES6 : <p>I have a class, and another class that extends that class.</p>

<pre><code>class Shape {
  constructor() {
    return this;
  }
}
class Circle extends Shape {
  constructor() {
    super();
    return this;
  }
}
let foo = new Circle();
</code></pre>

<p>I can get foo's class with</p>

<pre><code>let className = foo.constructor.name 
// returns string 'Circle'
</code></pre>

<p>Is it possible to get the name of foo's superclass ('Shape') in a similar manner?</p>
