Javascript Inheritence

(function() {
var core = {
require : function(source) {
if ( typeof (source) != "object" || !source)
throw new TypeError("Object needed as source.");
for (var property in source)
if (source.hasOwnProperty(property) && !this.prototype.hasOwnProperty(property))
this.prototype[property] = source[property];
},
override : function(source) {
if ( typeof (source) != "object" || !source)
throw new TypeError("Object needed as source.");
for (var property in source)
if (source.hasOwnProperty(property))
this.prototype[property] = source[property];
},
extend : function(source) {
var superClass = this;
var newClass = source.hasOwnProperty("constructor") ? source.constructor : function() {
superClass.apply(this, arguments);
};
newClass.superClass = superClass;

        var superClone = function() {
        };
        superClone.prototype = superClass.prototype;
        newClass.prototype = new superClone();
        newClass.prototype.constructor = newClass;

        if (source)
            newClass.override(source);
        return newClass;
    }
};

core.require.call(Function, core);

Function.create = function (source){
    var newClass = source.hasOwnProperty("constructor") ? source.constructor : function() {};
    newClass.override(source);
    return newClass;
};
})();

var Vehicle = Function.create({
constructor : function(wheels) {
this.wheels = wheels;
}
});

var Truck = Vehicle.extend({
constructor : function(hp, wheels) {
this.horsepower = hp;
Vehicle.call(this, wheels);
},
printInfo : function() {
console.log('I am a truck and I have ' + this.horsepower + ' hp.');
}
});

var t = new Truck(4, 350);
t.printInfo();