Backbone.UnbindingView improves on the default Backbone.View by making it easy to clean up event listeners that aren't set up with declarative events.

class Foo.Views.Main extends Backbone.View
  initialize: ->
    _.bindAll @, "render"

    @collection.on "reset", @render

  render: ->
    bar = new Foo.Views.Bar
    @$el.append bar.render().el

    @

In this version, every time a new Foo.Views.Main is instantiated, @collection will gain an additional listener — i.e., on the fifth instance, render will run five times. The problem gets even worse if Foo.Views.Bar binds to a model or collection.

class Foo.Views.Main extends Backbone.UnbindingView
  initialize: ->
    _.bindAll @, "render"

    @bindings = []
    @bindTo @collection, "reset", @render

  render: ->
    @cleanUp()

    bar = new Foo.Views.Bar
    @$el.append bar.render().el

    @

Here, @bindTo takes a slightly less direct route than .on, pushing the event binding into the @bindings Array set up by initialize. @cleanUp clears the binding from @collection, so the reset event will only fire once. Hooray!

Even better, you can add automatic subview cleanup by adding just two lines. Put @child_views = [] in initialize, and push in the subviews you create:

render: ->
  @cleanUp()

  bar = new Foo.Views.Bar
  @$el.append bar.render().el
  @child_views.push bar

  @

Important note: Using Backbone.UnbindingView for a view means that any subviews put in @child_views must be extended from UnbindingView.

Issues and patches welcome!