The prototype property is a reference. Our Accountant object’s prototype contains a reference to the Person prototype. This has two very important implications. Firstly, if a change is made to a prototype, all objects with that prototype get the same change. If we have 2 Accountant objects that we made from our Accountant prototype, and we add an “age” property to the prototype then both Accountant objects will have an accessible age property.
By David Posin