ncu-q2.js

var Foo = function() {};
Foo.prototype.bark = function() {
  console.log('Foo barks');
};

var Bar = function() {};
Bar.prototype = Foo.prototype;
Bar.prototype.bark = function() {
  console.log('Bar barks');
};
      
var foo = new Foo();
var bar = new Bar();
foo.bark();
bar.bark();