event.rb

class Event < ApplicationRecord
  # Before
  def cateorized?
    event.category.present? ? event.category.name != 'none' : false
  end
  
  # Refactor - simplify with Null test with AND operator
  def categorized?
    event.category && event.category != 'none'
  end

  # Refactored with Null Object pattern with duck typing but it still violates Law of Demeter
  def categorized?
    (event.category.presence || OpenStruct.new(name: 'none')).name != 'none'
  end
end

# Refactor #2 - add delegate to class
class Event
  delegate :categorized?, to: :category
end

class Category < ApplicationRecord
  def categorized?
    name && name != 'none'
  end
end