Merge backbone views (mixin pattern)

backbone-mixin.js

define('backbone', ['lib-underscore', 'lib-backbone'], function () {
  Backbone.mixin = function (view, mixin, custom) {
    if (custom) {
      if (custom.events && mixin.events) {
        mixin = _.clone(mixin)
        _.defaults(custom.events, mixin.events)
      }
      _.extend(mixin, custom)
    }
    var source = view.prototype || view
    _.defaults(source, mixin)
    if (mixin.events) {
      if (source.events) {
        _.defaults(source.events, mixin.events)
      } else {
        source.events = mixin.events
      }
    }
    if (mixin.initialize !== undefined) {
      var oldInitialize = source.initialize
      source.initialize = function () {
          mixin.initialize.apply(this, arguments)
          oldInitialize.apply(this, arguments)
        }
    }
  }
  return Backbone
})

usage.js

/* 
 * usage:
 *   Backboen.mixin(source, mixin, [custom])
 */

var FigureSection = Backbone.View.extend({
    tagName: 'p'
  , initialize: function(options) {
      return
    }
})

Backbone.mixin(FigureSection, FigureCaptionEditorMixin, {
    onOpenEditCaption: function() {
      this.openCaptionEditorHeight = this.$el.height()
    }
  , onUpdateCaption: function() {
      if (this.openCaptionEditorHeight > this.$el.height()) {
        this.$el.trigger('mouseleave')
      }
    }
})