Advices for better logic/performance on rendering a list in Backbone

Question

I'm really new to web developing and Backbone. I would like some advices for better performance on this program I have written. I tried to write a program similar to these: React vs AngularJS vs KnockoutJS: a Performance Comparison

In particular, I'd like to know if $( "#insideID" ).detach(); is a good strategy or not.

Here is part of my code:

<script id="itemTemplate" type="text/template">
<%= name %>
</script>  

        $( document ).ready(function() {

            // Model
            var Item = Backbone.Model.extend({
            });

            // Collection
            var ItemsCollection = Backbone.Collection.extend({
                model: Item
            });


            // View for all elements
            var ItemsView = Backbone.View.extend({
                className: 'inside',
                id: 'insideID',

                render: function() {
                    this.collection.each(function(item) {
                        var itemView = new ItemView({ model: item });
                        this.$el.append(itemView.render().el);
                    }, this);

                    return this;
                }
            });

            // View for a single element
            var ItemView = Backbone.View.extend({
                tagName : 'span',

                template: _.template($('#itemTemplate').html() ),

                render: function() {
                    this.$el.html( this.template(this.model.toJSON()) );
                    return this;
                }
            });


            var runBackbone = document.getElementById("run-backbone");
            runBackbone.addEventListener("click", function() {

            var data = _buildData(); //It returns an array of strings

            date = new Date();

            $( "#insideID" ).detach();

            // It creates the collection
            var itemsCollection = new ItemsCollection;

            for (var i = 0; i < data.length; i++)
            {
                newItem = new Item ({name: data[i].label});
                itemsCollection.add(newItem);
            }

            var itemsView = new ItemsView({ collection: itemsCollection });
            $("#col-12").append(itemsView.render().el);

            runBackbone.innerHTML = (new Date() - date) + " ms";


            });

            });

Answer 1

In your itemsView render method, instead of appending each itemView to your element, causing many DOM reflows especially if you have many items in your collection, you could use a documentFragment as a container that you append only one time.

render: function() {
    this.$el.empty();

    var container = document.createDocumentFragment();

    this.collection.each(function(item) {
        var itemView = new ItemView({ model: item });
        container.appendChild(itemView.render().el);
    }, this);

    this.$el.append(container);
    return this;
} 

Answer 2

You might want to check out Marionette framework. It will help you if your application starts to get bigger and complex (eg grids, layouts, compositeViews etc), Backbone Marionette