How to add methods to a (JSON) object's prototype?

Question

Let\'s say I receive some JSON object from my server, e.g. some data for a Person object:

{firstName: \"Bjarne\", lastName: \"Fisk\"}

Now,

Answer 1

In other words you want to change prototype (a.k.a. class) of existing object. Technically you can do it this way:

var Person = {
  function fullName() { return this.firstName + " " + this.lastName; }
};

// that is your PROFIT function body: 
personData.__proto__ = Person ;

After that if you will get true on personData instanceof Person