lazy-model-list.js

var AttrProto = Y.Attribute.prototype,
    GlobalEnv = YUI.namespace('Env.Model'),
    Lang      = Y.Lang,
    YArray    = Y.Array,

    EVT_ADD   = 'add',
    EVT_ERROR = 'error',
    EVT_RESET = 'reset';

Y.LazyModelList = Y.Base.create('lazyModelList', Y.ModelList, [], {
    // -- Public Methods -------------------------------------------------------
    get: function (name) {
        if (this.attrAdded(name)) {
            return AttrProto.get.apply(this, arguments);
        }

        return YArray.map(this._items, function (item) {
            return item[name];
        });
    },

    getAsHTML: function (name) {
        if (this.attrAdded(name)) {
            return Y.Escape.html(AttrProto.get.apply(this, arguments));
        }

        return YArray.map(this._items, function (item) {
            return Y.Escape.html(item[name]);
        });
    },

    getAsURL: function (name) {
        if (this.attrAdded(name)) {
            return encodeURIComponent(AttrProto.get.apply(this, arguments));
        }

        return YArray.map(this._items, function (item) {
            return encodeURIComponent(item[name]);
        });
    },

    indexOf: function (model) {
        return YArray.indexOf(model._isYUIModel ?
            this._models : this._items, model);
    },

    reset: function (models, options) {
        models  || (models  = []);
        options || (options = {});

        var facade = Y.merge({src: 'reset'}, options);

        if (models._isYUIModelList) {
            models = models.toArray(); // assume we'll get an array of plain objects (for now)
        }

        facade.models = models;

        if (options.silent) {
            this._defResetFn(facade);
        } else {
            // Sort the models before firing the reset event.
            if (this.comparator) {
                models.sort(Y.bind(this._sort, this));
            }

            this.fire(EVT_RESET, facade);
        }

        return this;
    },

    toJSON: function () {
        return this.toArray();
    },

    revive: function (item) {
        return Lang.isNumber(item) ?
                this._reviveIndex(item) : this._reviveObject(item);
    },

    // -- Protected Methods ----------------------------------------------------

    // Generates ad-hoc clientIds for non-instantiated models.
    _generateClientId: function () {
        GlobalEnv.lastId || (GlobalEnv.lastId = 0);
        return this.model.NAME + '_' + (GlobalEnv.lastId += 1);
    },

    _reviveIndex: function (index) {
        return this._models[index] || this._reviveObject(this._items[index], index);
    },

    _reviveObject: function (model, index) {
        if (!model) {
            return null;
        }

        if (!model._isYUIModel) {
            model = new this.model(model);
            this._attachList(model);
        }

        if (index || index === 0) {
            this._models[index] = model;
        }

        return model;
    },

    _isInList: function (item) {
        return ('clientId' in item && this._clientIdMap[item.clientId]) ||
                ('id' in item && this._idMap[item.id]);
    },

    _add: function (item, options) {
        var facade;

        options || (options = {});

        // Ensure that the item has a clientId.
        'clientId' in item || (item.clientId = this._generateClientId());

        if (this._isInList(item)) {
            this.fire(EVT_ERROR, {
                error: 'Model is already in the list.',
                model: item,
                src  : 'add'
            });

            return;
        }

        facade = Y.merge(options, {
            index: 'index' in options ? options.index : this._findIndex(item),
            model: item
        });

        options.silent ? this._defAddFn(facade) : this.fire(EVT_ADD, facade);

        return item;
    },

    _clear: function () {
        YArray.each(this._models, this._detachList, this);

        this._clientIdMap = {};
        this._idMap       = {};
        this._items       = [];
        this._models      = [];
    },

    _remove: function (item, options) {
        // If the given item is a model instance, turn it into an index before
        // calling the parent _remove method, since we only want to deal with
        // the plain object version.
        if (item._isYUIModel) {
            item = this.indexOf(item);
        }

        return Y.ModelList.prototype._remove.call(this, item, options);
    },

    // -- Default Event Handlers -----------------------------------------------
    _defAddFn: function (e) {
        var item = e.model;

        this._clientIdMap[item.clientId] = item;

        if (Lang.isValue(item.id)) {
            this._idMap[item.id] = item;
        }

        this._items.splice(e.index, 0, item);
    },

    _defRemoveFn: function (e) {
        var index = e.index,
            item  = e.model,
            model = this._models[index];

        delete this._clientIdMap[item.clientId];

        if ('id' in item) {
            delete this._idMap[item.id];
        }

        if (model) {
            this._detachList(model);
            this._models.splice(index, 1);
        }

        this._items.splice(index, 1);
    }
});