Backbone.Subviews

A minimalist view mixin for creating and managing subviews in your Backbone.js applications.

This plugin is designed to manage a fixed number of subviews. See Backbone.CollectionView for a plugin to manage a dynamic number of subviews (i.e. an array of subviews, or a "collection" of subviews).

Benefits

Provides a clean, consistent syntax for subviews in templates: <div data-subview="mySubview"></div>
Automatically places references to subviews in a hash keyed by name: this.subviews.mySubview
Maintains subview objects when a parent view is re-rendered, preserving subview state.
Automatically cleans up (i.e. removes) subviews when a parent view is removed.
Promotes small encapsulated ui components that can be reused with parcelify or cartero.
Can be mixed into any view class.

Example

In a view template, insert a subview "mySubview" using a placeholder div with a data-subview attribute:

<script type='text/template' id="MyItemViewTemplate">
	<h1>This is my item view template</h1>

	<div data-subview="mySubview"></div>
</script>

Now in MyItemView.js:

MyItemViewClass = Backbone.View.extend( {
	initialize : function() {
		// Add backbone.subview functionality to this view.
		Backbone.Subviews.add( this );
	},

	subviewCreators : {
		"mySubview" : function() {
			var options = {};

			// Do any logic required to create initialization options,
			// then instantiate and return the new subview object.
			return new MySubviewClass( options );
		}
	},

	render : function( data ) {
		// `render` funciton is just like normal.. nothing new here.
		var templateFunction = _.template( $( "#MyItemViewTemplate" ).html() );
		this.$el.html( templateFunction( data ) );

		// after we are done rendering, our subviews will automatically be rendered in order
	},

	onSubviewsRendered : function() {
		// This method (if it exists) is called after subviews are finished rendering.
		// Anytime after subviews are rendered, you can find the subviews in the `subviews` hash

		this.listenTo( this.subviews.mySubview, "highlighted", this._mySubview_onHighlighted );
	},

	...
} );

Usage

To insert a subview, just put <div data-subview="[subviewName]"></div> in the appropriate place in the parent view's template. This placeholder div will be completely replaced with the subview's DOM element.

Then include an entry for the subview in the subviewCreators hash. The key of each entry in this hash is a subview's name, and the value is a function that should create and return the new subview object.

After the parent view's render function is finished, the subviews will automatically be created and rendered (in the order their placeholder divs appear inside the parent view). Once all subviews have been created and rendered, the parent view's onSubviewsRendered method is called (if one exists).

When a parent view is re-rendered, its subviews will be re-rendered (i.e. their render function will be called). By default the original subview objects will by reused in order to preserve subview state. To force the subview objects to be recreated instead of reused, call parentView.removeSubviews() before re-rendering the parent.

A parent view will automatically remove all its subviews when its remove method is called.

Template Helpers

To further simplify the syntax for inserting subviews in your templates, add a global template helper to your template language of choice. For example, with underscore.js templates, the underscore-template-helpers mixin can be used to support this syntax:

<script type='text/template' id="MyItemViewTemplate">
	<h1>This is my item view template</h1>

	<%= subview( "mySubview" ) %>
</script>

Change log

v0.7.2 (4/13/14)

Improved UMD wrapper to use DOM library already attached to jquery.

v0.7.1 (4/6/14)

Relax div restriction on subview placeholder - placeholders can now be of any type of element.

v0.7 (2/26/14)

UMD wrapper and package.json added.

v0.6 (1/10/14)

Renamed _onSubviewsRendered to onSubviewsRendered. (Old name depreciated but still works for now.)
Added view.removeSubviews() method.

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