Classical OO languages usually have a special syntax that gives you access to the parent class, also referred to as superclass. This could be convenient when a child wants to have a method that does everything the parent's method does plus something in addition. In such cases, the child calls the parent's method with the same name and works with the result.

In JavaScript, there is no such special syntax, but it's easy to achieve the same functionality. Let's rewrite the last example and, while taking care of inheritance, also create an uber property that points to the parent's prototype object.

function Shape(){}
// augment prototype
Shape.prototype.name = 'shape';
Shape.prototype.toString = function(){
  var result = [];
  if (this.constructor.uber) {
    result[result.length] = this.constructor.uber.toString();
  }
  result[result.length] = this.name;
  return result.join(', ');
};

function TwoDShape(){}
// take care of inheritance
var F...