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This is the primary documentation for the Marionette API. Here, you'll find detailed discussion of the individual pieces of Marionette, the basics of how to use them, and how to customize them to work in manners that fit your applicaton's needs.

Please note that this is document is rather dry - it's meant to be a reference for those that just need a reference. If you're looking for an introduction and/or examples on how to get started, please see the Wiki.

Marionette's Pieces

These are the strings that you can pull to make your puppet dance:

The Application, Region, ItemView and CollectionView use the extend syntax and functionality from Backbone, allowing you to define new versions of these objects with custom behavior.

Marionette.Application

The Backbone.Marionette.Application object is the hub of your composite application. It organizes, initializes and coordinates the various pieces of your app. It also provides a starting point for you to call into, from your HTML script block or from your JavaScript files directly if you prefer to go that route.

The Application is meant to be instantiated directly, although you can extend it to add your own functionality.

MyApp = new Backbone.Marionette.Application();

Adding Initializers

Your application needs to do useful things, like displaying content in your regions, starting up your routers, and more. To accomplish these tasks and ensure that your Application is fully configured, you can add initializer callbacks to the application.

MyApp.addInitializer(function(options){
  // do useful stuff here
  var myView = new MyView({
    model: options.someModel
  });
  MyApp.mainRegion.show(myView);
});

MyApp.addInitializer(function(options){
  new MyAppRouter();
  Backbone.history.start();
});

These callbacks will be executed when you start your application, and are bound to the application object as the context for the callback. In other words, this is the MyApp object, inside of the initializer function.

The options parameters is passed from the start method (see below).

Initializer callbacks are guaranteed to run, no matter when you add them to the app object. If you add them before the app is started, they will run when the start method is called. If you add them after the app is started, they will run immediately.

Application Event

The Application object raises a few events during its lifecycle. These events can be used to do additional processing of your application. For example, you may want to pre-process some data just before initialization happens. Or you may want to wait until your entire application is initialized to start the Backbone.history.

The events that are currently triggered, are:

  • "initialize:before": fired just before the initializers kick off
  • "initialize:after": fires just after the initializers have finished
  • "start": fires after all initializers and after the initializer events
MyApp.bind("initialize:before", function(options){
  options.moreData = "Yo dawg, I heard you like options so I put some options in your options!"
});

MyApp.bind("initialize:after", function(options){
  if (Backbone.history){
    Backbone.history.start();
  }
});

The options parameter is passed through the start method of the application object (see below).

Starting An Application

Once you have your application configured, you can kick everything off by calling: MyApp.start(options).

This function takes a single optional parameter. This parameter will be passed to each of your initializer functions, as well as the initialize events. This allows you to provide extra configuration for various parts of your app, at initialization/start of the app, instead of just at definition.

var options = {
  something: "some value",
  another: "#some-selector"
};

MyApp.start(options);

app.vent: Event Aggregator

Every application instance comes with an instance of Marionette.EventAggregator called app.vent.

MyApp = new Backbone.Marionette.Application();

MyApp.vent.on("foo", function(){
  alert("bar");
});

MyApp.vent.trigger("foo"); // => alert box "bar"

See the Marionette.EventAggregator documentation below, for more details.

Marionette.Application.module

Marionette allows you to define a module within your application, including sub-modules hanging from that module.

This is useful for creating modular, encapsulated applications that are be split apart in to multiple files.

By default, every module that you define and add to your application, including sub-modules, is a new Application object instance. This allows you to have unlimited sub-modules and nesting. It also means you have all of the features and functionality of an Application object for each module.

Basic Usage

A module is defined directly from an Application object, and creates another Application object with the specified name:

var MyApp = new Backbone.Marionette.Application();

var myModule = MyApp.module("MyModule");

MyApp.MyModule; // => a new Marionette.Application object

myModule === MyApp.MyModule; // => true

If you specify the same module name more than once, the first instance of the module will be retained and a new instance will not be created.

Module Definitions

You can specify a callback function to provide a definition for the module. Module definitions are invoked immediately on calling module method.

The module definition callback will receive 6 parameters:

  • The module itself
  • The Parent module or Application object that .module was called from
  • Backbone
  • Backbone.Marionette
  • jQuery
  • Underscore

You can add functions and data directly to your module to make them publicly accessible. You can also add private functions and data by using locally scoped variables.

MyApp.module("MyModule", function(MyModule, MyApp, Backbone, Marionette, $, _){

  // Private Data And Functions
  // --------------------------

  var myData = "this is private data";
 
  var myFunction = function(){
    console.log(myData);
  }


  // Public Data And Functions
  // -------------------------

  MyModule.someData = "public data";

  MyModule.someFunction = function(){
    console.log(MyModule.someData);
  }
});

console.log(MyApp.MyModule.someData); //=> public data
MyApp.MyModule.someFunction(); //=> public data

Defining Sub-Modules With . Notation

Sub-modules can be defined in a number of ways.

You can define a module, and then later use that module to define sub-modules:

MyModule = MyApp.module("MyModule");
MyModule.module("SubModule");

MyApp.MyModule.SubModule; // => a valid module object

Or you can define an entire hierarchy of modules and sub-modules all at once:

MyApp.module("Parent.Child.GrandChild");

MyApp.Parent.Child.GrandChild; // => a valid module object

When defining sub-modules using the dot-notation, the parent modules do not need to exist. They will be created for you if they don't exist. If they do exist, though, the existing module will be used instead of creating a new one.

Starting A Sub-Module

As each module is an Application object instance, initializer functions can be registerd on your modules. There is no automatic starting of these modules, though. If you wish to use the module's initializer functions, you must manually call the module's start method.

MyApp.module("MyModule", function(MyModule){

  MyModule.addInitializer(function(){
    console.log("I'm a module initializer!");
  });

});

MyApp.MyModule.start(); // => "I'm a module initializer!"

Custom Module Objects

If you want to override the module object with your own object, you can do that by returning an object from the module definition:

MyApp.module("MyModule", function(){
  var customModule = {};


  return customModule;
});

MyApp.MyModule; // => the 'customModule' object

Note: When you override a module with a custom object, you will not be able to add sub-modules to it using the module fuction, as this function will not exist on your module (unless you add it yourself).

Splitting A Module Definition Apart

Sometimes a module gets to be too long for a single file. In this case, you can split a module definition across multiple files:

MyApp.module("MyModule", function(MyModule){
  MyModule.definition1 = true;
});

MyApp.module("MyModule", function(MyModule){
  MyModule.definition2 = true;
});

MyApp.MyModule.definition1; //=> true
MyApp.MyModule.definition2; //=> true

Note that if you return a custom module from your module definitions, the last module definition to return, wins.

MyApp.module("MyModule", function(MyModule){
  a = {};

  a.foo = "bar";

  return a;
});

MyApp.module("MyModule", function(MyModule){
  b = {};

  b.foo = "I'm overriding you!";

  return b;
});

MyApp.MyModule.foo; //=> "I'm overriding you!"

Marionette.AppRouter

Reduce the boilerplate code of handling route events and then calling a single method on another object. Have your routers configured to call the method on your object, directly.

Configure Routes

Configure an AppRouter with appRoutes. The route definition is passed on to Backbone's standard routing handlers. This means that you define routes like you normally would. Instead of providing a callback method that exists on the router, though, you provide a callback method that exists on the controller that you specify for the router instance (see below).

MyRouter = Backbone.Marionette.AppRouter.extend({
  appRoutes: {
    "some/route": "someMethod"
  }
});

You can also add standard routes to an AppRouter, with methods on the router.

Specify A Controller

App routers can only use one controller object. You can either specify this directly in the router definition:

someController = {
  someMethod: function(){ /*...*/ }
};

Backbone.Marionette.AppRouter.extend({
  controller: someController
});

Or in a parameter to the contructor:

myObj = {
  someMethod: function(){ /*...*/ }
};

new MyRouter({
  controller: myObj
});

Or

The object that is used as the controller has no requirements, other than it will contain the methods that you specified in the appRoutes.

It is recommended that you divide your controller objects into smaller pieces of related functionality and have multiple routers / controllers, instead of just one giant router and controller.

Marionette.Region

Region managers provide a consistent way to manage your views and show / close them in your application. They use a jQuery selector to show your views in the correct place. They also call extra methods on your views to facilitate additional functionality.

Defining An Application Region

Regions can be added to the application by calling the addRegions method on your application instance. This method expects a single hash parameter, with named regions and either jQuery selectors or Region objects. You may call this method as many times as you like, and it will continue adding regions to the app.

MyApp.addRegions({
  mainRegion: "#main-content",
  navigationRegion: "#navigation"
});

As soon as you call addRegions, your region managers are available on your app object. In the above example MyApp.mainRegion and MyApp.navigationRegion would be available for use immediately.

If you specify the same region name twice, the last one in wins.

Initialize A Region With An el

You can specify an el for the region manager to manage at the time that the region manager is instantiated:

var mgr = new Backbone.Marionette.Region({
  el: "#someElement"
});

Basic Usage

Once a region manager has been defined, you can call the show and close methods on it to render and display a view, and then to close that view:

var myView = new MyView();

// render and display the view
MyApp.mainRegion.show(myView);

// closes the current view
MyApp.mainRegion.close();

If you replace the current view with a new view by calling show, it will automatically close the previous view.

// show the first view
var myView = new MyView();
MyApp.mainRegion.show(myView);

// replace view with another. the
// `close` method is called for you
var anotherView = new AnotherView();
MyApp.mainRegion.show(anotherView);

Set How View's el Is Attached

You can specify a second parameter to the show method, which will be used to determine how the HTML from the view's el is attached to the DOM region that is being managed.

The options include any valid jQuery DOM object method, such as html, text, append, etc.

MyApp.mainRegion.show(myView, "append");

This example will use jQuery's $.append function to append the new view to the current HTML.

WARNING: Be careful when using this feature, as the view you are replacing may not be managed / closed correctly as a result. This can cause unexpected behavior, memory leaks or other problems. Use At Your Own Risk

Attach Existing View

There are some scenarios where it's desirable to attach an existing view to a region manager, without rendering or showing the view, and without replacing the HTML content of the region. For example, SEO and accessibiliy often need HTML to be generated by the server, and progressive enhancement of the HTML.

There are two ways to accomplish this:

  • set the currentView in the region manager's constructor
  • call attachView on the region manager instance

Set currentView On Initialization

var myView = new MyView({
  el: $("#existing-view-stuff")
});

var manager = new Backbone.Marionette.Region({
  el: "#content",
  currentView: myView
});

Call attachView On Region

MyApp.addRegions({
  someRegion: "#content"
});

var myView = new MyView({
  el: $("#existing-view-stuff")
});

MyApp.someRegion.attachView(myView);

Region Events And Callbacks

A region manager will raise a few events during its showing and closing of views:

  • "view:show" - when the view has been rendered and displayed
  • "onShow" - called on the region when the view has been rendered
  • "view:closed" - when the view has been closed

You can bind to these events and add code that needs to run with your region manager, opening and closing views.

MyApp.mainRegion.on("view:show", function(view){
  // manipulate the `view` or do something extra
  // with the region manager via `this`
});

MyApp.mainRegion.on("view:closed", function(view){
  // manipulate the `view` or do something extra
  // with the region manager via `this`
});

MyRegion = Backbone.Marionette.Region.extend({
  // ...

  onShow: function(view){
    // the `view` has been shown
  }
});

View Callbacks And Events For Regions

The region manager will call an onShow method on the view that was displayed. It will also trigger a "show" event from the view:

MyView = Backbone.View.extend({
  onShow: function(){
    // the view has been shown
  }
});

view = new MyView();

view.on("show", function(){
  // the view has been shown.
});

MyApp.mainRegion.show(view);

Defining A Custom Region

You can define a custom region manager by extending from Region. This allows you to create new functionality, or provide a base set of functionality for your app.

Once you define a region manager type, you can still call the addRegions method. Specify the region manager type as the value - not an instance of it, but the actual constructor function.

var FooterRegion = Backbone.Marionette.Region.extend({
  el: "#footer"
});

MyApp.addRegions({footerRegion: FooterRegion});

Note that if you define your own Region object, you must provide an el for it. If you don't, you will receive an runtime exception saying that an el is required.

Instantiate Your Own Region

There may be times when you want to add a region manager to your application after your app is up and running. To do this, you'll need to extend from Region as shown above and then use that constructor function on your own:

var SomeRegion = Backbone.Marionette.Region.extend({
  el: "#some-div",

  initialize: function(options){
    // your init code, here
  }
});

MyApp.someRegion = new SomeRegion();

MyApp.someRegion.show(someView);

You can optionally add an initialize function to your Region definition as shown in this example. It receives the options that were passed to the constructor of the Region, similar to a Backbone.View.

jQuery Deferred And Asynchronous Template Loading

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.View

Marionette has a base Marionette.View type that other views extend from. This base view provides some common and core functionality for other views to take advantage of.

Note: The Marionette.View type is not intended to be used directly. It exists as a base view for other view types to be extended from, and to provide a common location for behaviors that are shared across all views.

View.triggers

Views can define a set of triggers as a hash, which will convert a DOM event in to a view.trigger event.

The left side of the hash is a standard Backbone.View DOM event configuration, while the right side of the hash is the view event that you want to trigger from the view.

MyView = Backbone.Marionette.ItemView.extend({
  // ...

  triggers: {
    "click .do-something": "something:do:it"
  }
});

view = new MyView();
view.render();

view.on("something:do:it", function(){
  alert("I DID IT!");
});

// "click" the 'do-something' DOM element to 
// demonstrate the DOM event conversion
view.$(".do-something").trigger("click");

The result of this is an alert box that says, "I DID IT!"

You can also specify the triggers as a function that returns a hash of trigger configurations

Backbone.Marionette.CompositeView.extend({
  triggers: function(){
    return {
      "click .that-thing": "that:i:sent:you"
    };
  }
});

Triggers work with all View types that extend from the base Marionette.View.

View.serializeData

The serializeData method will serialize a view's model or collection - with precedence given to collections. That is, if you have both a collection and a model in a view, calling the serializeData method will return the serialized collection.

View.templateHelpers

There are times when a view's template needs to have some logic in it, and the view engine itself will not provide an easy way to accomplish this. For example, Underscore templates do not provide a helper method mechanism while Handlebars templates do.

A templateHelpers attribute can be applied to any View object that uses the serializeData method - including ItemViews, Layouts and CompositeViews. When this attribute is present, it's contents will be mixed in to the data object that comes back from the serializeData method for you. This will allow you to create helper methods that can be called from within your templates.

Basic Example

<script id="my-template" type="text/html">
  I think that <%= showMessage() %>
</script>
MyView = Backbone.Marionette.ItemView.extend({
  template: "#my-template",

  templateHelpers: {
    showMessage: function(){
      return this.name + " is the coolest!"
    }
  }

});

model = new Backbone.Model({name: "Backbone.Marionette"});
view = new MyView();
view.render(); //=> "I think that Backbone.Marionette is the coolest!";

Accessing Data Within The Helpers

In order to access data from within the helper methods, you need to prefix the data you need with this. Doing that will give you all of the methods and attributes of the serialized data object, including the other helper methods.

templateHelpers: {
  something: function(){
    return "Do stuff with " + this.name + " because it's awesome.";
  }
}

Object Or Function As templateHelpers

You can specify an object literal (as shown above), a reference to an object literal, or a function as the templateHelpers.

If you specify a function, the function will be invoked with the current view instance as the context of the function. The function must return an object that can be mixed in to the data for the view.

Backbone.Marionette.ItemView.extend({
  templateHelpers: function(){
    return {
      foo: function(){ /* ... */ }
    }
  }
});

Marionette.Layout

Formerly known as CompositeRegion.

A Layout is a specialized hybrid between an ItemView and a collection of Region objects, used for rendering an application layout with multiple sub-regions to be managed by specified region managers.

A layout manager can also be used as a composite-view to aggregate multiple views and sub-application areas of the screen where multiple region managers need to be attached to dynamically rendered HTML.

The Layout extends directly from ItemView and adds the ability to specify regions which become Region instances that are attached to the layout.

Basic Usage

<script id="layout-template" type="text/template">
  <section>
    <navigation id="menu">...</navigation>
    <article id="content">...</navigation>
  </section>
</script>
AppLayout = Backbone.Marionette.Layout.extend({
  template: "#layout-template",

  regions: {
    menu: "#menu",
    content: "#content"
  }
});

var layout = new AppLayout();
layout.render();

Once you've rendered the layout, you now have direct access to all of the specified regions as region managers.

layout.menu.show(new MenuView());

layout.content.show(new MainContentView());

Nested Layouts And Views

Since the Layout extends directly from ItemView, it has all of the core functionality of an item view. This includes the methods necessary to be shown within an existing region manager.

MyApp = new Backbone.Marionette.Application();
MyApp.addRegions({
  mainRegion: "#main"
});

var layout = new AppLayout();
MyApp.mainRegion.show(layout);

layout.show(new MenuView());

You can nest layouts into region managers as deeply as you want. This provides for a well organized, nested view structure.

Closing A Layout

When you are finished with a layout, you can call the close method on it. This will ensure that all of the region managers within the layout are closed correctly, which in turn ensures all of the views shown within the regions are closed correctly.

If you are showing a layout within a parent region manager, replacing the layout with another view or another layout will close the current one, the same it will close a view.

All of this ensures that layouts and the views that they contain are cleaned up correctly.

Event Aggregator

It's common to use a Layout to represent a sub-application in a larger overall application. Often the components of the sub-application need to communicate with each other without allowing the other parts of the larger application in on the communication. To facilitate this, the layout manager includes an event aggregator, vent.

var layout = new MyAppLayout();

layout.vent.trigger("stuff:was:done");

Marionette.ItemView

An ItemView is a view that represents a single item. That item may be a Backbone.Model or may be a Backbone.Collection. Whichever it is, though, it will be treated as a single item.

ItemView render

An item view has a render method built in to it, and uses the Renderer object to do the actual rendering.

The render function of the item view will return a jQuery promise object.

You should provide a template attribute on the item view, which will be either a jQuery selector:

MyView = Backbone.Marionette.ItemView.extend({
  template: "#some-template"
});

new MyView().render().done(function(){
  // the view is done rendering. do stuff here
});

or a function that returns a jQuery selector:

MyView = Backbone.Marionette.ItemView.extend({
  template: function(){
    if (this.model.get("foo")){
      return "#some-template";
    } else {
      return "#a-different-template";
    }
  }
});

new MyView().render().done(function(){
  // the view is done rendering. do stuff here
});

Callback Methods

There are several callback methods that are called for an ItemView. These methods are intended to be handled within the view definition, directly.

beforeRender callback

Before an ItemView is rendered a beforeRender method will be called on the view.

Backbone.Marionette.ItemView.extend({
  beforeRender: function(){
    // set up final bits just before rendering the view's `el`
  }
});

onRender callback

After the view has been rendered, a onRender method will be called. You can implement this in your view to provide custom code for dealing with the view's el after it has been rendered:

Backbone.Marionette.ItemView.extend({
  onRender: function(){
    // manipulate the `el` here. it's already
    // been rendered, and is full of the view's
    // HTML, ready to go.
  }
});

beforeClose callback

A beforeClose method will be called on the view, just prior to closing it:

Backbone.Marionette.ItemView.extend({
  beforeClose: function(){
    // manipulate the `el` here. it's already
    // been rendered, and is full of the view's
    // HTML, ready to go.
  }
});

onClose callback

An onClose method will be called on the view, after closing it.

Backbone.Marionette.ItemView.extend({
  onClose: function(){
    // custom closing and cleanup goes here
  }
});

View Events

There are several events that are triggers by an ItemView, which allow code outside of a view to respond to what's happening with the view.

"item:before:render" event

An "item:before:render" event will be triggered just before the view is rendered

MyView = Backbone.Marionette.ItemView.extend({...});

var myView = new MyView();

myView.on("item:before:render", function(){
  alert("the view is about to be rendered");
});

"render" / "item:rendered" event

An "item:rendered" event will be triggered just after the view has been rendered.

MyView = Backbone.Marionette.ItemView.extend({...});

var myView = new MyView();

myView.on("item:rendered", function(){
  alert("the view was rendered!");
});

myView.on("render", function(){
  alert("the view was rendered!");
});

"item:before:close" event

An "item:before:close" event will be triggered just prior to the view closing itself. This event fires when the close method of the view is called.

MyView = Backbone.Marionette.ItemView.extend({...});

var myView = new MyView();

myView.on("item:before:close", function(){
  alert("the view is about to be closed");
});

myView.close();

"item:closed" event

An "item:closed" event will be triggered just after the view closes. This event fires when the close method of the view is called.

MyView = Backbone.Marionette.ItemView.extend({...});

var myView = new MyView();

myView.on("item:closed", function(){
  alert("the view is closed");
});

myView.close();

ItemView serializeData

Item views will serialize a model or collection, by default, by calling .toJSON on either the model or collection. If both a model and collection are attached to an item view, the model will be used as the data source. The results of the data serialization will be passed to the template that is rendered.

If the serialization is a model, the results are passed in directly:

var myModel = new MyModel({foo: "bar"});

new MyItemView({
  template: "#myItemTemplate",
  model: myModel
});

MyItemView.render();
<script id="myItemTemplate" type="template">
  Foo is: <%= foo %>
</script>

If the serialization is a collection, the results are passed in as an items array:

var myCollection = new MyCollection([{foo: "bar"}, {foo: "baz"}]);

new MyItemView({
  template: "#myCollectionTemplate",
  collection: myCollection
});

MyItemView.render();
<script id="myCollectionTemplate" type="template">
  <% _.each(items, function(item){ %>
    Foo is: <%= foo %>
  <% }); %>
</script>

If you need custom serialization for your data, you can provide a serializeData method on your view. It must return a valid JSON object, as if you had called .toJSON on a model or collection.

Backbone.Marionette.ItemView.extend({
  serializeData: function(){
    return {
      "some attribute": "some value"
    }
  }
});

Binding To ItemView Events

ItemView extends Marionette.BindTo. It is recommended that you use the bindTo method to bind model and collection events.

MyView = Backbone.Marionette.ItemView.extend({
  initialize: function(){
    this.bindTo(this.model, "change:foo", this.modelChanged);
    this.bindTo(this.collection, "add", this.modelAdded);
  },

  modelChanged: function(model, value){
  },

  modelAdded: function(model){
  }
});

The context (this) will automatically be set to the view. You can optionally set the context by passing in the context object as the 4th parameter of bindTo.

ItemView close

ItemView implements a close method, which is called by the region managers automatically. As part of the implementation, the following are performed:

  • unbind all bindTo events
  • unbind all custom view events
  • unbind all DOM events
  • remove this.el from the DOM
  • call an onClose event on the view, if one is provided

By providing an onClose event in your view definition, you can run custom code for your view that is fired after your view has been closed and cleaned up. This lets you handle any additional clean up code without having to override the close method.

Backbone.Marionette.ItemView.extend({
  onClose: function(){
    // custom cleanup or closing code, here
  }
});

Marionette.CollectionView

The CollectionView will loop through all of the models in the specified collection, render each of them using a specified itemView, then append the results of the item view's el to the collection view's el.

Callback Methods

There are several callback methods that can be provided on a CollectionView. If they are found, they will be called by the view's base methods. These callback methods are intended to be handled within the view definition directly.

beforeRender callback

A beforeRender callback will be called just prior to rendering the collection view.

Backbone.Marionette.CollectionView.extend({
  beforeRender: function(){
    // do stuff here
  }
});

onRender callback

After the view has been rendered, a onRender method will be called. You can implement this in your view to provide custom code for dealing with the view's el after it has been rendered:

Backbone.Marionette.CollectionView.extend({
  onRender: function(){
    // do stuff here
  }
});

beforeClose callback

This method is called just before closing the view.

Backbone.Marionette.CollectionView.extend({
  beforeClose: function(){
    // do stuff here
  }
});

onClose callback

This method is called just after closing the view.

Backbone.Marionette.CollectionView.extend({
  onClose: function(){
    // do stuff here
  }
});

CollectionView Events

There are several events that will be triggered during the life of a collection view. These are intended to be handled from code external to the view.

"collection:before:render" event

Triggers just prior to the view being rendered

MyView = Backbone.Marionette.CollectionView.extend({...});

var myView = new MyView();

myView.on("collection:before:render", function(){
  alert("the collection view is about to be rendered");
});

myView.render();

"render" / "collection:rendered" event

A "collection:rendered" event will also be fired. This allows you to add more than one callback to execute after the view is rendered, and allows parent views and other parts of the application to know that the view was rendered.

MyView = Backbone.Marionette.CollectionView.extend({...});

var myView = new MyView();

myView.on("render", function(){
  alert("the collection view was rendered!");
});

myView.on("collection:rendered", function(){
  alert("the collection view was rendered!");
});

myView.render();

"collection:before:close" event

Triggered just before closing the view.

MyView = Backbone.Marionette.CollectionView.extend({...});

var myView = new MyView();

myView.on("collection:before:close", function(){
  alert("the collection view is about to be closed");
});

myView.close();

"collection:closed" event

Triggered just after closing the view.

MyView = Backbone.Marionette.CollectionView.extend({...});

var myView = new MyView();

myView.on("collection:closed", function(){
  alert("the collection view is now closed");
});

myView.close();

"itemview:*" event bubbling from child views

When an item view within a collection view triggers an event, that event will bubble up through the parent collection view, with "itemview:" prepended to the event name.

That is, if a child view triggers "do:something", the parent collection view will then trigger "itemview:do:something".

// set up basic collection
var myModel = new MyModel();
var myColelction = new MyCollection();
myCollection.add(myModel);

// get the collection view in place
colView = new CollectionView({
  collection: myCollection
});
colView.render();

// bind to the collection view's events that were bubbled
// from the child view
colView.on("itemview:do:something", function(childView, msg){
  alert("I said, '" + msg + "'");
});

// hack, to get the child view and trigger from it
var childView = colView.children[myModel.cid];
childView.trigger("do:something", "do something!");

The result of this will be an alert box that says "I said, 'do something!'".

Also note that you would not normally grab a reference to the child view the way this is showing. I'm merely using that hack as a way to demonstrate the event bubbling. Normally, you would have your item view listening to DOM events or model change events, and then triggering an event of it's own based on that.

CollectionView render

The render method of the collection view is responsible for rendering the entire collection. It loops through each of the items in the collection and renders them individually as an itemView.

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.

MyCollectionView = Backbone.Marionette.CollectionView.extend({...});

new MyCollectionView().render().done(function(){
  // all of the children are now rendered. do stuff here.
});

CollectionView's itemView

Specify an itemView in your collection view definition. This must be a Backbone view object definition (not instance). It can be any Backbone.View or be derived from Marionette.ItemView.

MyItemView = Backbone.Marionette.ItemView.extend({});

Backbone.Marionette.CollectionView.extend({
  itemView: MyItemView
});

Alternatively, you can specify an itemView in the options for the constructor:

MyCollectionView = Backbone.Marionette.CollectionView.extend({...});

new MyCollectionView({
  itemView: MyItemView
});

If you do not specify an itemView, an exception will be thrown stating that you must specify an itemView.

CollectionView: Automatic Rendering

The collection view binds to the "add", "remove" and "reset" events of the collection that is specified.

When the collection for the view is "reset", the view will call render on itself and re-render the entire collection.

When a model is added to the collection, the collection view will render that one model in to the collection of item views.

When a model is removed from a collection (or destroyed / deleted), the collection view will close and remove that model's item view.

CollectionView: Re-render Collection

If you need to re-render the entire collection, you can call the view.render method. This method takes care of closing all of the child views that may have previously been opened.

CollectionView's appendHtml

By default the collection view will call jQuery's .append to move the HTML contents from the item view instance in to the collection view's el.

You can override this by specifying an appendHtml method in your view definition. This method takes two parameters and has no return value.

Backbone.Marionette.CollectionView.extend({
  appendHtml: function(collectionView, itemView){
    collectionView.$el.prepend(itemView.el);
  }
});

The first parameter is the instance of the collection view that will receive the HTML from the second parameter, the current item view instance.

CollectionView close

CollectionView implements a close method, which is called by the region managers automatically. As part of the implementation, the following are performed:

  • unbind all bindTo events
  • unbind all custom view events
  • unbind all DOM events
  • unbind all item views that were rendered
  • remove this.el from the DOM
  • call an onClose event on the view, if one is provided

By providing an onClose event in your view definition, you can run custom code for your view that is fired after your view has been closed and cleaned up. This lets you handle any additional clean up code without having to override the close method.

Backbone.Marionette.CollectionView.extend({
  onClose: function(){
    // custom cleanup or closing code, here
  }
});

Marionette.CompositeView

A CompositeView extends from CollectionView to be used as a composite view for scenarios where it should represent both a branch and leaf in a tree structure, or for scenarios where a collection needs to be rendered within a wrapper template.

For example, if you're rendering a treeview control, you may want to render a collection view with a model and template so that it will show a parent item with children in the tree.

You can specify a modelView to use for the model. If you don't specify one, it will default to the Marionette.ItemView.

CompositeView = Backbone.Marionette.CompositeView.extend({
  template: "#leaf-branch-template"
});

new CompositeView({
  model: someModel,
  collection: someCollection
});

For more examples, see my blog post on using the composite view

Composite Render

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
});

Composite Model Template

When a CompositeView is rendered, the model will be rendered with the template that the view is configured with. You can override the template by passing it in as a constructor option:

new MyComp({
  template: "#some-template"
});

Recursive By Default

The default rendering mode for a CompositeView assumes a hierarchical, recursive structure. If you configure a composite view without specifying an itemView, you'll get the same composite view type rendered for each item in the collection. If you need to override this, you can specify a itemView in the composite view's definition:

var ItemView = Backbone.Marionette.ItemView.extend({});

var CompView = Backbone.Marionette.CompositeView.extend({
  itemView: ItemView
});

Model And Collection Rendering

The model and collection for the composite view will re-render themselves under the following conditions:

  • When the collection's "reset" event is fired, it will re-render the entire list
  • When the collection has a model added to it (the "add" event is fired), it will render that one item to the rendered list
  • When the collection has a model removed (the "remove" event is fired), it will remove that one item from the rendered list

You can also manually re-render either or both of them:

  • If you want to re-render everything, call the .render() method
  • If you want to re-render the model's view, you can call .renderModel()
  • If you want to re-render the collection's views, you can call .renderCollection()

Events And Callbacks

During the course of rendering a composite, several events will be triggered:

  • "composite:item:rendered" - after the modelView has been rendered
  • "composite:collection:rendered" - after the collection of models has been rendered
  • "render" / "composite:rendered" - after everything has been rendered

Additionally, after the composite view has been rendered, an onRender method will be called. You can implement this in your view to provide custom code for dealing with the view's el after it has been rendered:

Backbone.Marionette.CompositeView.extend({
  onRender: function(){
    // do stuff here
  }
});

Marionette.EventAggregator

An event aggregator is an application level pub/sub mechanism that allows various pieces of an otherwise segmented and disconnected system to communicate with each other.

Basic Usage

Backbone.Marionette provides an event aggregator with each application instance: MyApp.vent. You can also instantiate your own event aggregator:

myVent = new Backbone.Marionette.EventAggregator();

Passing an object literal of options to the constructor function will extend the event aggregator with those options:

myVent = new Backbone.Marionette.EventAggregator({foo: "bar"});
myVent.foo // => "bar"

BindTo

The EventAggregator extends from the BindTo object (see below) to easily track and unbind all event callbacks, including inline callback functions.

The bindTo method, though, has been proxied to only take 3 arguments. It assumes that the object being bound to is the event aggregator directly, and does not allow the bound object to be specified:

vent = new Backbone.Marionette.EventAggregator();

vent.bindTo("foo", function(){
  alert("bar");
});

vent.unbindAll();

vent.trigger("foo"); // => nothing. all events have been unbound.

Decoupling With An Event-Driven Architecture

You can use an event aggregator to communicate between various modules of your application, ensuring correct decoupling while also facilitating functionality that needs more than one of your application's modules.

var vent = new Backbone.Marionette.EventAggregator();

vent.bind("some:event", function(){
  alert("Some event was fired!!!!");
});
  
vent.trigger("some:event");

For a more detailed discussion and example of using an event aggregator with Backbone applications, see the blog post: References, Routing, and The Event Aggregator: Coordinating Views In Backbone.js

Marionette.BindTo

The BindTo object provides event binding management and facilitates simple event binding and unbinding for any object that extends from Backbone.Events.

Bind Events

var binder = _.extend({}, Backbone.Marionette.BindTo);

var model = new MyModel();

var handler = {
  doIt: function(){}
}
binder.bindTo(model, "change:foo", handler.doIt);

You can optionally specify a 4th parameter as the context in which the callback method for the event will be executed:

binder.bindTo(model, "change:foo", someCallback, someContext);

Unbind A Single Event

When you call bindTo, it returns a "binding" object that can be used to unbind from a single event with the unbindFrom method:

var binding = binder.bindTo(model, "change:foo", someCallback, someContext);

// later in the code
binder.unbindFrom(binding);

This will unbind the event that was configured with the binding object, and remove it from the BindTo bindings.

Unbind All Events

You can call unbindAll to unbind all events that were bound with the bindTo method:

binder.unbindAll();

This even works with in-line callback functions.

Backbone.Marionette.Renderer

The Renderer object was extracted from the ItemView rendering process, in order to create a consistent and re-usable method of rendering a template with or without data.

Basic Usage

The basic usage of the Renderer is to call the render method. This method returns a jQuery promise object, which will provide the HTML that was rendered when it resolves.

var template = "#some-template";
var data = {foo: "bar"};
var render = Backbone.Marionette.Renderer.render(template, data);

render.done(function(html){
  // do something with the HTML here
});

Custom Template Selection And Rendering

By default, the renderer will take a jQuery selector object as the first parameter, and a JSON data object as the optional second parameter. It then uses the TemplateCache to load the template by the specified selector, and renders the template with the data provided (if any) using Underscore.js templates.

If you wish to override the way the template is loaded, see the TemplateCache object.

If you wish to override the template engine used, change the renderTemplate method to work however you want:

Backbone.Marionette.Renderer.renderTemplate = function(template, data){
  return $(template).tmpl(data);
});

This implementation will replace the default Underscore.js rendering with jQuery templates rendering.

Pre-Loaded Templates With RequireJS

It's common for developers to use RequireJS to pre-load the entire template that is needed. When the template is pre-loaded like this, the use of a jQuery selector is not needed.

If you wish to replace the entire rendering process, based on the assumption that you will always pre-load the entire template for your view, it can be done by replacing the render method on the Renderer object:

Backbone.Marionette.Renderer.render = function(template, data){
  return _.template(template, data);
};

This will skip the TemplateCache usage entirely, and all of the other code that is usually run, and return the compiled template immediately.

Caching Pre-Compiled Templates

There's a performance hit in replacing the entire render function of the Renderer object as shown in the example above. You should only have to compile a template once, and you should be caching the pre-compiled template after that.

To accomplish this, avoid replacing the render function. Instead use a combination of the renderTemplate function and the TemplateCache.loadTemplate function.

Backbone.Marionette.TemplateCache.loadTemplate = function(template, callback){
  // pre-compile the template and store that in the cache.
  var compiledTemplate = _.template(template);
  callback.call(this, compiledTemplate);
};

Backbone.Marionette.Renderer.renderTemplate = function(template, data){
  // because `template` is the pre-compiled template object,
  // we only need to execute the template with the data
  return template(data);
}

For more information about the TemplateCache.loadTemplate function, see the next section of the documentation.

Backbone.Marionette.TemplateCache

The TemplateCache provides a cache for retrieving templates from script blocks in your HTML. This will improve the speed of subsequent calls to get a template.

Basic Usage

To use the TemplateCache, call it directly. It is not instantiated like other Marionette objects.

Get A Template

Templates are retrieved using a jQuery selector by default, and are handed back to you via a callback method. The template is returned as a plain string.

Backbone.Marionette.TemplateCache.get("#my-template", function(template){
 // use the template here
});

Making multiple calls to get the same template will retrieve the template from the cache on subsequence calls:

var a, b, c;
Backbone.Marionette.TemplateCache.get("#my-template", function(tmpl){a = tmpl});
Backbone.Marionette.TemplateCache.get("#my-template", function(tmpl){b = tmpl});
Backbone.Marionette.TemplateCache.get("#my-template", function(tmpl){c = tmpl});
a === b === c; // => true

Override Template Retrieval

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.loadTemplate = function(templateId, callback){
  // load your template here, returning it or a deferred
  // object that resolves with the template as the only param
}

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

Clear Items From cache

You can clear one or more, or all items from the cache using the clear method. Clearing a template from the cache will force it to re-load from the DOM (or from the overriden loadTemplate function) the next time it is retrieved.

If you do not specify any parameters, all items will be cleared from the cache:

Backbone.Marionette.TemplateCache.get("#my-template");
Backbone.Marionette.TemplateCache.get("#this-template");
Backbone.Marionette.TemplateCache.get("#that-template");

// clear all templates from the cache
Backbone.Marionette.TemplateCache.clear()

If you specify one or more parameters, these parameters are assumed to be the templateId used for loading / caching:

Backbone.Marionette.TemplateCache.get("#my-template");
Backbone.Marionette.TemplateCache.get("#this-template");
Backbone.Marionette.TemplateCache.get("#that-template");

// clear 2 of 3 templates from the cache
Backbone.Marionette.TemplateCache.clear("#my-template", "#this-template")

Built In To ItemView

If you're using Marionette.ItemView, you don't need to manually call the TemplateCache. Just specify the template attribute of your view as a jQuery selector, and the ItemView will use the template manager by default.

Backbone.Marionette.Callbacks

The Callbacks object assists in managing a collection of callback methods, and executing them, in an async-safe manner.

Basic Usage

There are only three methods:

  • add
  • run
  • setOptions

The add method adds a new callback to be executed later.

The run method executes all current callbacks in, using the specified context for each of the callbacks, and supplying the provided options to the callbacks.

var callbacks = new Backbone.Marionette.Callbacks();

callbacks.add(function(options){
  alert("I'm a callback with " + options.value + "!");
});

callbacks.run(someContext, {value: "options"});

This example will display an alert box that says "I'm a callback with options!". The executing context for each of the callback methods has been set to the someContext object, which can be any valid JavaScript object.

Advanced / Async Use

The Callbacks executes each callback in an async-friendly manner, and can be used to facilitate async callbacks. The Marionette.Application object uses Callbacks to manage initializers (see above).

It can also be used to guarantee callback execution in an event driven scenario, much like the application initializers.