factory.js

function FactoriaVehiculos() {
    this.createVehicle = function (type) {
        var vehicle;
 
        if (type === "coche") {
            vehicle = new Coche();
        } else if (type === "moto") {
            vehicle = new Moto();
        } else if (type === "autobus") {
            vehicle = new Autobus();
        } else if (type === "sidecar") {
            vehicle = new Sidecar();
        }
 
        vehicle.type = type;
 
        vehicle.say = function () {
            log.add(this.type + " tiene " + this.wheel + " Ruedas");
        }
 
        return vehicle;
    }
}
 
var Coche = function () {
    this.wheel = 4;
};
 
var Moto = function () {
    this.wheel = 2;
};
 
var Autobus = function () {
    this.wheel = 8;
};
 
var Sidecar = function () {
    this.wheel = 3;
};
 
// log helper
var log = (function () {
    var log = "";
 
    return {
        add: function (msg) { log += msg + "\n"; },
        show: function () { alert(log); log = ""; }
    }
})();
 
function run() {
    var vehicles = [];
    var factory = new FactoriaVehiculos();
 
    vehicles.push(factory.createVehicle("moto"));
    vehicles.push(factory.createVehicle("coche"));
    vehicles.push(factory.createVehicle("autobus"));
    vehicles.push(factory.createVehicle("sidecar"));
    
    for (var i = 0, len = vehicles.length; i < len; i++) {
        vehicles[i].say();
    }
 
    log.show();
}