ruby-on-rails - rails 5 : ActiveRecord collection index_by

Question

使用索引方法将应用程序升级到 Rails 5。问题是它不会递增到下一个 ActiveRecord 集合记录。下面的代码用于在 Rails 4.0 中工作。尝试使用index_by。

def next_question
  index = campaign.quiz_questions.index self
  campaign.quiz_questions[index + 1]
end

调试器

(byebug) campaign.quiz_questions.index
*** NoMethodError Exception: undefined method `index' for #<QuizQuestion::ActiveRecord_Associations_CollectionProxy:0x007f80012d71b0>
Did you mean?  index_by

使用index_by

(byebug) index = campaign.quiz_questions.index_by
#<Enumerator: #<ActiveRecord::Associations::CollectionProxy [#<QuizQuestion id: 113, campaign_id: 492, message: "Where did Hullabalooza's freak show manager send H...", created_at: "2016-07-20 20:50:32", updated_at: "2016-07-20 20:50:32">]>:index_by>

索引 + 1

(byebug) index + 1
*** NoMethodError Exception: undefined method `+' for #<Enumerator:0x007fc4db445960>

nil

Answer 1

将其更改为find_index方法。现在可以运行了

def next_question
  index = campaign.quiz_questions.find_index self
  campaign.quiz_questions[index + 1]
end