A Backbone View container, using Q for promises. Expects children with a `transitionIn` and `transitionOut` function that return promises.

ViewContainer.js

define(function( require, exports, module ){

    var _ = require('underscore'),
        Backbone = require('backbone'),
        Q = require('q');


    /**
     * This is a generic view that manages additional children views
     * use `addChild` and `removeChild` to nest a view within
     */
    var View = Backbone.View.extend({
        initialize: function( opts ){
            _.bindAll(this, 'remove', 'removeChild','transitionIn', 'transitionOut', 'render');
            this.children = [];
            this.options = opts || {};
        },
        /**
         * add a child to the view
         * @param {Backbone.View} view the view to add.
         */
        addChild: function( view ){
          this.children.push(view);
          this.trigger('add', view);
        },
        /**
         * remove a child from the view
         * @param {Backbone.View} view the view to remove.
         * @return {Boolean} true if the view was removed
         */
        removeChild: function( view ){
            if( _.contains(this.children, view) ){
                view.remove();
                this.children = _.without(this.children, view);
                this.trigger('remove', view);
                return true;
            }
            return false;
        },
        remove: function(){
            _.each(this.children, this.removeChild);
            return Backbone.View.prototype.remove.call(this);
        },
        render: function(){
            _.invoke(this.children,'render');
            _.each(this.children, function(c){ this.append(c.$el); }, this.$el);
            return this;
        },
        transitionIn: function( opts ){
            //simultaneously call transitionIn on all elements,
            //resolve promise when all are done
            return Q.all(_.invoke(this.children, 'transitionIn', opts));
        },
        transitionOut: function(){
            //simultaneously call transitionOut on all elements,
            //resolve promise when all are done
            return Q.all(_.invoke(this.children,'transitionOut'))
                .done(this.remove, this.remove);
        }
    });


    return View;
});