Rails：用块重构代码

Question

我使用 Rails 4.2，我想重构我的辅助方法以去除重复代码：

在app/helpers/admin/tasks_helper.rb

def chosen_select(name, method, chzes, selected = nil, options = {}, html_options = {})
  options[:value_method] ||= :id
  options[:text_method] ||= :name
  if options.key?(:placeholder)
    html_options['data-placeholder'.intern] = options[:placeholder]
    options.delete(:placeholder)
  end
  if html_options.key?(:class)
    html_options[:class] = 'chosen-select ' + html_options[:class]
  else
    html_options[:class] = 'chosen-select'
  end
  chzes = options_from_collection_for_select(chzes, options[:value_method], options[:text_method], selected)
  options.delete(:value_method)
  options.delete(:text_method)
  select(name, method, chzes, options.merge!(include_hidden: false), html_options)
end

def chosen_select_array(name, method, chzes, selected = nil, options = {}, html_options = {})
  options[:value_method] ||= :id
  options[:text_method] ||= :name
  if options.key?(:placeholder)
    html_options['data-placeholder'.intern] = options[:placeholder]
    options.delete(:placeholder)
  end
  if html_options.key?(:class)
    html_options[:class] = 'chosen-select ' + html_options[:class]
  else
    html_options[:class] = 'chosen-select'
  end
  chzes = options_for_select(chzes, selected)
  options.delete(:value_method)
  options.delete(:text_method)
  select(name, method, chzes, options.merge!(include_hidden: false), html_options)
end

我认为我有很多方法调用，例如 app/views/admin/tasks/index。html.erb

  <%= chosen_select(:select, :project_id, [TaskFilterOptgroups.active_projects, TaskFilterOptgroups.inactive_projects] , @task_filter_configuration.project_id, {:include_blank => true, :placeholder => 'Project'}, {'data-last-project_id' => @task_filter_configuration.project_id, :style => 'width: 150px;'}) %>

这样我就不想更改视图中的方法调用。我的尝试是制作一个通用方法 "chosen_select_generic" ，它将从特定方法调用，例如 "chosen_select":

def chosen_select_generic(name, method, chzes, selected = nil, options = {}, html_options = {})
  options[:value_method] ||= :id
  options[:text_method] ||= :name
  if options.key?(:placeholder)
    html_options['data-placeholder'.intern] = options[:placeholder]
    options.delete(:placeholder)
  end
  if html_options.key?(:class)
    html_options[:class] = 'chosen-select ' + html_options[:class]
  else
    html_options[:class] = 'chosen-select'
  end
  # 2 different chzes in 2 methods:
  # 1) chosen_select(...)
  # chzes = options_from_collection_for_select(chzes, options[:value_method], options[:text_method], selected)
  # 2) chosen_select_array(...)
  # chzes = options_for_select(chzes, selected)     
  yield chzes 
  options.delete(:value_method)
  options.delete(:text_method)
  select(name, method, chzes, options.merge!(include_hidden: false), html_options)
end

然后 chosen_select 可能看起来像：

def chosen_select(name, method, chzes, selected = nil, options = {}, html_options = {})
  chosen_select_generic(name, method, chzes, selected = nil, options = {}, html_options = {}) do |contents|
    chzes = option_groups_from_collection_for_select(chzes, :entries, :status, options[:value_method], options[:text_method], selected)
  end
end

但这不起作用。如何在不更改视图中的方法调用的情况下提取块中的重复代码？

Answer 1

你块中的这个作业不会按照你的想法去做：

chzes = option_groups_from_collection_for_select(...)

它创建一个新的局部变量而不是改变外部变量。如果它是这里唯一可以改变的部分，那么你可以 return 它来自块：

chosen_select_generic(name, method, chzes, selected = nil, options = {}, html_options = {}) do |chzes|
  option_groups_from_collection_for_select(chzes, :entries, :status, options[:value_method], options[:text_method], selected)
end

然后像这样在您的通用方法中接收值：

chzes = yield(chzes)

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