Ruby 2.4/Rails 5:生成递归哈希数组,如果键为空则删除

我有一个类似这样的类,它将集合转换为哈希的嵌套数组:

# variable_stack.rb
class VariableStack
  def initialize(document)
    @document = document
  end

  def to_a
    @document.template.stacks.map { |stack| stack_hash(stack) }
  end

  private

  def stack_hash(stack)
    {}.tap do |hash|
      hash['stack_name'] = stack.name.downcase.parameterize.underscore
      hash['direction'] = stack.direction
      hash['boxes'] = stack.boxes.indexed.map do |box|
        box_hash(box)
      end.reverse_if(stack.direction == 'up') # array extensions
    end.delete_if_key_blank(:boxes) # hash extensions
  end

  def box_hash(box)
    {}.tap do |hash|
      hash['box'] = box.name.downcase.parameterize.underscore
      hash['content'] = box.template_variables.indexed.map do |var|
        content_array(var)
      end.join_if_any?
    end.delete_if_key_blank(:content)
  end

  def content_array(var)
    v = @document.template_variables.where(master_id: var.id).first
    return unless v
    if v.text.present?
      v.text
    elsif v.photo_id.present?
      v.image.uploaded_image.url
    else
      ''
    end
  end
end

# array_extensions.rb
class Array
  def join_if_any?
    join("\n") if size.positive?
  end

  def reverse_if(boolean)
    reverse! if boolean
  end
end

# hash_extensions.rb
class Hash
  def delete_if_key_blank(key)
    delete_if { |_, _| key.to_s.blank? }
  end
end

该方法应该返回如下所示的哈希:

"stacks": [
{
  "stack_name": "stack1",
  "direction": "down",
  "boxes": [
    {
      "box": "user_information",
      "content": "This is my name.\n\nThis is my phone."
    }
},
{
  "stack_name": "stack2",
  "direction": "up",
  "boxes": [
    {
      "box": "fine_print",
      "content": "This is a test.\n\nYeah yeah."
    }
  ]
}

相反,box键通常为null:

"stacks": [
{
  "stack_name": "stack1",
  "direction": "down",
  "boxes": null
},
{
  "stack_name": "stack2",
  "direction": "up",
  "boxes": [
    {
      "box": "fine_print",
      "content": "This is a test.\n\nYeah yeah."
    }
  ]
}

我怀疑这是因为我无法在Rails 5中“单行”添加阵列(即,它们被冻结)。这个 @document.template.stacks 是ActiveRecord集合。

hash['boxes'] ?

失败的测试

APIDocumentV3 Instance methods #stacks has the correct content joined and indexed
 Failure/Error:
   expect(subject.stacks.first['boxes'].first['content'])
     .to include(document.template_variables.first.text)

   expected "\n" to include "#1"
   Diff:
   @@ -1,2 +1 @@
   -#1

存在 \n