Flyweight proxy ArrayList for fast DataTable instantiation and rendering

gistfile1.js

var proxy = {
        _data: {},
        get: function (name) {
            var model = this._data;

            return model.isYUIModel ?
                model.apply(model, arguments) :
                model[name];
        },
        set: function () {
            this._vivify();

            return this._data.set.apply(this._data, arguments);
        },
        setAttrs: function () {
            this._vivify();

            return this._data.setAttrs.apply(this._data, arguments);
        },
        _vivify: function () {
            if (!this._data._isYUIModel) {
                this._data = new this.model(this._data);
            }
        },
        toJSON: function () {
            var model = this._data;

            return model._isYUIModel ? model.toJSON() : model;
        },
        addTarget: function () {}
    },

    DataList = Y.extend(function (items) {
        Y.ArrayList.apply(this, arguments);
    }, Y.ArrayList, {
        getAttrs: function () {},
        addTarget: function () {},
        each: function (fn, context) {
            var items = this._items,
                i, len, item;

            for (i = 0, len = items.length; i < len; ++i) {
                item = this._item(i);

                fn.call(context || item, item, i, this);
            }

            return this;
        },
        _item: function (i) {
            var model = this._items[i];

            return model._isYUIModel ? model : ((proxy._data = model) && proxy);
        },
        item: function (i) {
            var model = this._items[i];

            if (!model.isYUIModel) {
                model = this._items[i] = new this.model(model);
            }

            return model;
        }
    });

// Usage example
var table = new Y.DataTable({
    columns: [ ... ],
    recordType: [ <same as above> ], // needed as temporary patch for this to work
    data: new DataList([ <lots of objects> ])
});