class.js

define([], function () {
    'use strict';

    var Class = function (classProp) {
        var parentClass = classProp.extends;

        var Clazz = function (attributes) {
            // load default values from class attributes
            attributes = defaults(attributes, classProp.attributes);

            // --- call parent class's constructor
            if (parentClass !== undefined) {
                // load default values from parent class attributes
                attributes = defaults(attributes, parentClass.defaultAttributes);

                parentClass.call(this, attributes);
            }

            this.attributes = attributes;

            // call class's init method
            var init = classProp.init;
            if(init!==undefined) {
                init.call(this);
            }

            // bind "this" to "this.attributes"
            // TODO: bind to this.attributes to change scope?
            // TODO: is this a good idea?
            for(var name in classProp.methods) {
                this[name] = this[name].bind(this.attributes);
            }
        };

        // --- use parent class's prototype
        if (parentClass !== undefined) {
            Clazz.prototype = Object.create(parentClass.prototype);
        }

        // --- declare prototype methods
        for (var methodName in classProp.methods) {
            Clazz.prototype[methodName] = classProp.methods[methodName];
        }

        // --- special stuff
        Clazz.defaultAttributes = classProp.attributes;
        Clazz.init = classProp.init;

        // --- private functions
        function defaults(attributes, defaultAttributes) {
            attributes = attributes || {};
            for (var names in defaultAttributes) {
                if (attributes[names] === undefined) {
                    // attribute not specified during object creation, set the default
                    attributes[names] = defaultAttributes[names];
                }
            }

            return attributes;
        }

        return Clazz;
    };

    return Class;
});