Following just the summarize discuss in gitter:

Following is toto error:

• get '/(*other)', to: 'hyperloop#app', which introduce in Chapter 7, should mention in Chapter 1, other, rails route not worked, I do this myself when follow this tuto, but others maybe not.

• after rails g hyperloop:install, and then copy application_record.rb into app/hyperloop/models, that not work, uninitialized constant ApplicationRecord, the solution is: add config.import 'models/application_record' into config/initializers/hyperloop.rb, and rm tmp/cache, then worked.
  this step is done in this project, but when follow tuto, no where told us.

Follow is some advice for hyperloop

Following usage i think is error-prone.
EditItem(todo: params.todo).on(:save, :cancel) { mutate.editing false }
In most case, :save, :cancel should be browser internal event,
If we use a event like this but name conflict with this, what happen?
and, use param to define a event is very strange for me.

I think a better idea is: (two selection)

• Not use on method, not conflict with browser event, you just hope yield
  one behavior only, use a name other than on is better, or, just simple:

# replace EditItem(todo: params.todo).on(:save, :cancel) { mutate.editing false }
# with

EditItem(
        todo:      params.todo,
        on_save:   proc { mutate.editing false },
        on_cancel: proc { mutate.editing false }
      )

# and invoke it like this:
params.on_save.call

• Not use param to declare a event. e.g.

def event(name)
  # detect all browser internal support event name, if conflict, raise a error.
  param name, type: Proc
end
event :on_save

I think first solution is better, because params.on_save is just like usual param,
it just use logic instead of a variable.