Question

I am using some code that uses this syntax (restful authentication).

def logged_in?
  !!current_user()
end

Tried googling for this but it just seems to ignore “!!”, will accept an answer that can tell me how to find info about searching for strings such as !! in google.

Answer 1

It’s double negation. The first ! converts it to false if current_user is not nil or false. After that it converts it to true. So the result is always a boolean value and not the value of current_user. The result is always true if current_user is not false or nil. Otherwise it’s false.