gistfile1.js

define([
    'underscore',
    'marionette',
    'vent',
    'views/mixins/resizable',
    'views/group/collection/item'
], function (
    _,
    Marionette,
    vent,
    ResizableViewMixin,
    GroupCollectionItemView
) {
    "use strict";

    var GroupCollectionView = Marionette.CollectionView.extend({
        initialize: function (options) {
            options = options || {};

            if (options) {
                this.parentGroupGuid = options.parentGroupGuid;
            }

            this.collection.listenTo(vent, 'group:created', function (model) {
                if (model.get('parent_group_guid') === this.parentGroupGuid) {
                    this.add(model);
                }
            }, this);
        },
        onClose: function () {
            this.collection.stopListening();
        },
        itemView: GroupCollectionItemView,
        tagName: 'ul'
    });

    return _.extend(GroupCollectionView.prototype, ResizableViewMixin);
});