js inheritance

var Person = function(firstName, lastName) {
  this.firstName = firstName;
  this.lastName = lastName;
}

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

var Worker = function(firstName, lastName, title) {
  Person.call(this, firstName, lastName);
  this.title = title;
}

Worker.prototype = Object.create(Person.prototype);
Worker.prototype.constructor = Worker;

Worker.prototype.professionalName = function() {
  return this.fullName() + ', ' + this.title;
}