Thanks for this, I have spent a lot of time trying different approaches of this for our app :).
IMO just adding the Javascript in the view is cleaner and easier to manage for us. Everything is in one place relating to the view.
Our app has 23 different controllers, each with several actions. Navigating all of those folders and different files, if we used this setup would be a pain.
Any idea why deleting _breadcrumbs.html.erb and putting the yield code it into application.html.haml was slower?
Interesting, can the same approach you share in this video be used in production?