清理引數哈希時減少AbcSize指標

我的購買控制器中有一個簡單的方法，可以在應用強引數之前從引數哈希調整用戶表單輸入。

def sanitize_params
  params[:purchase][:invoice] = nil if params[:purchase][:invoice] == ''
  params[:purchase][:note] = nil if params[:purchase][:note] == ''
  params[:purchase][:product_id] = nil if params[:purchase][:product_id].blank?
end

Rubocop 逮捕了Metrics/AbcSize… [<3, 19, 5> 19.87/17]. ABC 指標中的“分支”如何計算為 19？

我可以重構為：

def sanitize_params
  unsanitized_purchase_params = params[:purchase]
  params[:purchase][:invoice] = nil if unsanitized_purchase_params[:invoice] == ''
  params[:purchase][:note] = nil if unsanitized_purchase_params[:note] == ''
  params[:purchase][:product_id] = nil if unsanitized_purchase_params[:product_id].blank?
end

然后通過，但以犧牲可讀性和額外代碼為代價。為什么'Branch' 19 在原始代碼中？我應該關心嗎？（我的實際用例有一條額外的相似線，因此那里的指標更高）。有更好的方法嗎？謝謝丹尼爾

uj5u.com熱心網友回復：

如檔案所示：

分支——顯式轉發程式分支超出范圍——函式呼叫、類方法呼叫或新運算子

因此，ABC 中的“分支”被計算為“跳出當前方法的任何內容”。

在你描述的方法中，

def sanitize_params
  params[:purchase][:invoice] = nil if params[:purchase][:invoice] == ''
  params[:purchase][:note] = nil if params[:purchase][:note] == ''
  params[:purchase][:product_id] = nil if params[:purchase][:product_id].blank?
end

這些是需要離開當前方法的 19 個呼叫：

01. params (on line 1, before the assignment)
02. params[:purchase] (on line 1, before the assignment)
03. params[:purchase][:invoice] (on line 1, before the assignment)
04. params (on line 1, after the assignment)
05. params[:purchase] (on line 1, after the assignment)
06. params[:purchase][:invoice] (on line 1, after the assignment)

07. params (on line 2, before the assignment)
08. params[:purchase] (on line 2, before the assignment)
09. params[:purchase][:note] (on line 2, before the assignment)
10. params (on line 2, after the assignment)
11. params[:purchase] (on line 2, after the assignment)
12. params[:purchase][:note] (on line 2, after the assignment)

13. params (on line 3, before the assignment)
14. params[:purchase] (on line 3, before the assignment)
15. params[:purchase][:product_id] (on line 3, before the assignment)
16. params (on line 3, after the assignment)
17. params[:purchase] (on line 3, after the assignment)
18. params[:purchase][:product_id] (on line 3, after the assignment)
19. params[:purchase][:product_id].blank? (on line 3, after the assignment)

重要的 ponts：每當您呼叫 時params，您都在訪問不同的方法，并且每次您訪問散列上的索引時，您都是在此散列上呼叫一個方法來訪問所需的索引。

關于你是否應該關心：ABC 大小是衡量代碼質量的標準，所以當然，只要它有意義，堅持它通常是一個很好的選擇。

但是有一些方法可以重構代碼以降低 ABC 復雜性。一個建議如下：

def sanitize_params
  params.tap do |params|
    params[:purchase][:invoice] = nil if params.dig(:purchase, :invoice) == ''
    params[:purchase][:note] = nil if params.dig(:purchase, :note) == ''
    params[:purchase][:product_id] = nil if params.dig(:purchase, :product_id).blank?
  end
end

在這個例子中，Branch 的復雜性降低了很多，因為我們只呼叫了一次外部并應用了塊params內的所有更改。tap此外，通過使用dig引數上的方法，我們只呼叫一種方法來達到我們想要的深度。

例如，另一個想法是將這種方法分解為更具體的方法來清理每個屬性。

我希望這會有所幫助。

uj5u.com熱心網友回復：

至于現在 Rails 引數不實作#deep_transform_values!，但您可以執行以下操作：

def sanitize_params
  %i[invoice note product_id].each do |param_name|
    params[:purchase][param_name] = params[:purchase][param_name].presence
  end
end

要么：

def sanitize_params
  params[:purchase] = params[:purchase].transform_values(&:presence)
end

更新。您也可以考慮使用https://github.com/rmm5t/strip_attributes - 這個 gem 將在模型級別用 nils 替換空值

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