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Marionette.Async

Add async / deferred rendering and template loading to Backbone.Marionette

Download

To add support for asynchronously loading templates and rendering views, you need to download and include one of the following marionette.async builds in your project:

Development: backbone.marionette.async.js

Production: backbone.marionette.async.min.js

AMD/RequireJS Support

Note that there is no AMD/RequireJS build for Marionette.Async. AMD/RequireJS are asynchronous by definition: Asynchronous Module Definition. Providing an AMD/RequireJS version of Marionette.Async would be redundant.

Basic Usage

To use Marionette.Async, you must include one of the above downloads in your project, after Marionette has been included:

<script src="/js/underscore.js"></script>
<script src="/js/jquery.js"></script>
<script src="/js/json2.js"></script>
<script src="/js/backbone.js"></script>
<script src="/js/backbone.marionette.js"></script>
<script src="/js/backbone.marionette.async.js"></script>

Once that has been included, several core functions on several of the Marionette objects will be overwritten with asynchronous counterparts.

Note that this is destructive change. You cannot switch back and forth between sync/async objects. Once included in the page, all of the specified methods will run with async capabilities.

Marionette.Async.Region

The region manager show method takes advantage of jQuery's deferred cababilities, allowing for some very advanced techniques to be used for rendering views.

To use a deferred, a view that is shown via a region manager must return a jQuery deferred object from the render method:

DeferredView = Backbone.View.extend({
  render: function(){
    var that = this;
    var data = this.serializeData();
    var dfd = jQuery.Deferred();

    this.getTemplate(function(template){
      var html = that.renderTemplate(template, data);

      that.$el.html(html);

      if (that.onRender){
        that.onRender();
      }

      dfd.resolve();
    });

    return dfd.promise();
  }
});

var view = new DeferredView();
MyApp.mainRegion.show(view);

The region manager will wait until the deferred object is resolved before it attached the view's el to the DOM and displays it.

Marionette.Async.ItemView

The render method returns a jQuery deferred object, allowing you to know when the rendering completes.

Marionette.Async.CollectionView

The render method returns a jQuery deferred object, allowing you to know when the rendering completes. This deferred object is resolved after all of the child views have been rendered.

Marionette.Async.CompositeView

A composite view returns a jQuery deferred object from the render method. This allows you to know when the rendering for the entire composite structure has been completed.

MyComp = Backbone.Marionette.CompositeView.extend({...});

myComp = new MyComp().render().done(function(){
  // the entire composite is now rendered. do stuff here
});

Marionette.Async.TemplateCache

The default template retrieval is to select the template contents from the DOM using jQuery. If you wish to change the way this works, you can override the loadTemplate method on the TemplateCache object.

Backbone.Marionette.TemplateCache.prototype.loadTemplate = function(templateId, callback){
  // load your template here, returning it or a deferred
  // object that resolves with the template as the only param
  var myTemplate = ...;

  // send the template back
  callback(myTemplate);
}

For example, if you want to load templates asychronously from the server, instead of from the DOM, you could replace loadTemplate function.

If a "template.html" file exists on the server, with this in it:

<script id="my-template" type="text/template">
  <div>some template stuff</div>
</script>

Then the loadTemplate implementation may look like this:

Backbone.Marionette.TemplateCache.loadTemplate = function(templateId, callback){
  var that = this;
  var url = templateId + ".html";

  $.get(url, function(templateHtml){
    var template = $(tmplateHtml).find(templateId);
    callback(template);
  });
}

This will use jQuery to asynchronously retrieve the template from the server. When the get completes, the callback function will select the template from the resulting HTML and then call the callback function to send it in to the template cache and allow it to be used for rendering.

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