introduce-null-object.md

Introduce Null Object

Example

Before

username =
  if current_user.nil?
    "Guest"
  else
    current_user.name
  end

After

username = current_user.name

# ...

class LoggedInUser
  def name
    @name
  end

  # ...
end

class GuestUser
  def name
    "Guest"
  end

  # ...
end

References

Sandi Metz has a great video about the Null Object Pattern in Ruby, titled Nothing is Something.