Allows jQuery animation transitions between marionette regions

FadeTransitionRegion.js

var FadeTransitionRegion = Backbone.Marionette.Region.extend({

  show: function(view){
    this.ensureEl();
    view.render();

    this.close(function() {
	  if (this.currentView && this.currentView !== view) { return; }
      this.currentView = view;

  	  this.open(view, function(){
	    if (view.onShow){view.onShow();}
	    view.trigger("show");

	    if (this.onShow) { this.onShow(view); }
	    this.trigger("view:show", view);
	  });
	});

  },

  close: function(cb){
    var view = this.currentView;
    delete this.currentView;

    if (!view){
	  if (cb){ cb.call(this); }
	  return; 
	}

    var that = this;
    view.fadeOut(function(){
      if (view.close) { view.close(); }
      that.trigger("view:closed", view);
	  if (cb){ cb.call(that); }
    });

  },

  open: function(view, callback){
    var that = this;
    this.$el.html(view.$el.hide());
    view.fadeIn(function(){
      callback.call(that);
    });
  }

});