Refactoring blocks

models.rb

class Book < ActiveRecord::Base
  has_many :shelf_books
  has_many :shared_items, as: :item
  has_many :book_reviews
end

class ShelfBook < ActiveRecord::Base
  belongs_to :book
end

class SharedItem < ActiveRecord::Base
  belongs_to :item, polymorphic: true
end

class BookReview < ActiveRecord::Base
  belongs_to :book
end

rake_task.rb

def update_associated_records(old_book, new_book)
  update_shelf_books(old_book, new_book)
  update_shared_items(old_book, new_book)
  update_reviews(old_book, new_book)
end

def update_shelf_books(old_book, new_book, &block)
  old_book.shelf_books.map { |shelf_book| shelf_book.update(book: new_book) }
end

def update_shared_items(old_book, new_book)
  old_book.shared_items.map { |shared_item| shared_item.update(item: new_book) }
end

def update_reviews(old_book, new_book)
  old_book.book_reviews.map do |review|
    review.update(book: new_book)
    update_associated_activity(review) # this is the only part different from the others
  end
end