Factory pattern is soo simple in JavaScript

main.js

    function CarMaker() {}

    CarMaker.prototype.drive = function () {
        return "Vroom, I have " + this.doors + " doors";
    };
    CarMaker.factory = function (type) {
        var constr = type,
            newcar;

        if (typeof CarMaker[constr] !== "function") {
            throw {
                name: "Error",
                message: constr + " doesn't exist"
            };
        }
        if (typeof CarMaker[constr].prototype.drive !== "function") {
            CarMaker[constr].prototype = new CarMaker();
        }
        newcar = new CarMaker[constr]();

        return newcar;

    };
    CarMaker.Compact = function () {
        this.doors = 4;
    };
    CarMaker.Convertible = function () {
        this.doors = 2;
    };
    CarMaker.SUV = function () {
        this.doors = 24;
    }