Allow Region Manager to attach to existing el about backbone.marionette

[mxriverlynn]

the quick hack to work around this would be to attach your existing view to an existing element, and then to attach your view instance to the region manager manually. internally, the region manager stores the current view in this.currentView https://github.com/derickbailey/backbone.marionette/blob/master/backbone.marionette.js#L45

so you could do this:

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

MyApp.myRegion.currentView = myView;

This would get the view attached to the region manager, so that the next call to MyApp.myRegion.show(...) would close it properly, and all that. It would also avoid the whole-sale replacement of the existing content.

A better solution, which I plan to put in place, would be to have an attachView method on the region manager object. This method would attach an existing view to the region manager in the same way that I just suggested, but it would encapsulate that logic and anything else that needs to happen.

It might also be a good idea to allow a view to be passed in to a region constructor through the options:

var myView = new MyView();

new Backbone.Marionette.RegionManager({
  initialView: myView
});

and have this set up so that it will just attach the existing view without rendering and replacing what's currently there.

[mxriverlynn]

this is done in the dev branch. you can either initialize with currentView: myView or call attachView(myView)