Object instances without using this/new/prototype

person.js

var person = function(firstName, lastName) {
    return {
        getFullName: function() {
            return firstName + ' ' + lastName;
        },
        setFirstName: function(newName) {
            firstName = newName;
        },
        setLastName: function(newName) {
            lastName = newName;
        }
    };
};