Rails Routes: as-block and device_for block

Question

According to devise documentation, we can override the default session paths using the following:

as :user do
   get 'login', to: 'users/sessions#new', as: :new_user_session
   post 'login', to: 'users/sessions#create', as: :user_session
   delete 'logout', to: 'users/sessions#destroy', as: :destroy_user_session
end 

This will generate the following routes:

Helper Path                   URL        Controller
new_user_session_path        /login      users/sessions#new
user_session_path            /login      users/sessions#create
destroy_user_session_path    /logout     users/sessions#destroy

However, without wrapping the defined path inside an as-block or a devise_scope block, such as the one below, we produce the same exact routes.

get 'login', to: 'users/sessions#new', as: :new_user_session
post 'login', to: 'users/sessions#create', as: :user_session
delete 'logout', to: 'users/sessions#destroy', as: :destroy_user_session

My question is, why do we even need the as-block / device_for block? Why not just define it directly? What is the function and benefit of the as-block?

Answer 1

RESTful routes for devise looks like: devise_for :users ...

In any case, the as is equivalent to the devise_scope one, and they are designed for specifying your custom routes.

Here is the documentation on this question.