nil current_user response to json

Question

I found a demo app that implements devise with Backbone. In the layout file, it does this

$(function(){
        BackDevise.initialize(<%= current_user.to_json.html_safe %>);
    })

If I start the application without being logged in, there is obviously no current_user, but the application doesn't throw an error. Why? ie normally, when I use Devise with Rails, I have to do a lot of <% if current_user ... %> checks to see if the user is logged in. Why wouldn't this code need anything like that? Note, the code doesn't (as far as I can see) override the current_user helper provided by Devise, so I would have expected it to throw an exception if I'm not logged in.

Answer 1

原因nil响应to_json并返回"null"