如何使用 Sandi Metz 规则重写此代码片段？

Question

假设我有一个 Survey rails 模型 has_many: questions 并且需要能够重新排序问题...

我应该在哪里放置 renumber_questions 方法（调查模型、问题模型或其他 class，为什么？）以及如何在 [=14 之后最好地编写下面这个丑陋的方法=]?

  def renumber_questions
    last_page = 0
    new_page = 0
    new_seq = 0
    questions.unscope(:order).order(page: :asc, seq: :asc).each do |question|
      if last_page != question.page
        new_page = new_page + 1
      end
      last_page = question.page

      new_seq = new_seq + 1
      question.page = new_page
      question.seq = new_seq
      question.save
    end
  end

Answer 1

把它放在另一个 class 上，因为单一职责（在你给的 link 中提到）。

Despite the large number of private methods we wrote, keeping classes short proved easy. It forced us to consider what the single responsibility of our class was, and what should be extracted.

class RenumberQuestions
  def initialize(questions)
    @questions = questions.unscope(:order).order(page: :asc, seq: :asc)
    @last_page = 0
    @new_page = 0
    @new_seq = 0
  end

  def call
    @questions.each do |question|
      counting_var(question)
      mutate_(question)
    end
  end

  def counting_var(question)
    @new_page += 1 if @last_page != question.page
    @last_page = question.page
    @new_seq += 1
  end

  def mutate_(question)
    question.page = @new_page
    question.seq = @new_seq
    question.save
  end
end

抱歉命名错误。我不知道你是做什么的，所以我只是按照我的理解命名它。你可以让它更干净。

如何使用 Sandi Metz 规则重写此代码片段？

How to rewrite this code snippet using Sandi Metz rules?

ruby

class-design

model

ruby-on-rails