Сергей Доний

var human = (function (person) {
    this.person = {
        firstName : "John",
        lastName  : "Doe",
        age       : person.age || 50,
        eyeColor  : person.eyeColor || "blue",
    };
    this.getInfo = function () {return person.age + ", " + person.eyeColor; }
    return this;
});

var getPerson = new human({ eyeColor: "Yellow" });
//

console.log(getPerson.person, getPerson.getInfo());