diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index fcbd4074..c83b2894 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -2,6 +2,8 @@
 
 # Helpers
 module ApplicationHelper
+  BRACKETS = /[\[\]]/
+
   # Devuelve el atributo name de un campo anidado en el formato que
   # esperan los helpers *_field
   #
@@ -19,6 +21,14 @@ module ApplicationHelper
     [root, name]
   end
 
+  # Obtiene un ID
+  #
+  # @param base [String]
+  # @param attribute [String, Symbol]
+  def id_for(base, attribute)
+    "#{base.gsub(BRACKETS, '_')}_#{attribute}".squeeze('_')
+  end
+
   def plain_field_name_for(*names)
     root, name = field_name_for(*names)
 
diff --git a/app/views/posts/attributes/_new_array.haml b/app/views/posts/attributes/_new_array.haml
index 08fc6dee..b4407c0d 100644
--- a/app/views/posts/attributes/_new_array.haml
+++ b/app/views/posts/attributes/_new_array.haml
@@ -1,7 +1,7 @@
 -#
   Genera un listado de checkboxes entre los que se puede elegir para guardar
 :ruby
-  id = "#{base.gsub(/[\[\]]/, '_')}_#{attribute}".squeeze('_')
+  id = id_for(base, attribute)
   name = "#{base}[#{attribute}][]"
   form_id = "form-#{Nanoid.generate}"
 
diff --git a/app/views/posts/attributes/_new_has_many.haml b/app/views/posts/attributes/_new_has_many.haml
index 48230759..9382e2af 100644
--- a/app/views/posts/attributes/_new_has_many.haml
+++ b/app/views/posts/attributes/_new_has_many.haml
@@ -8,7 +8,7 @@
   del formulario principal porque no se pueden anidar.
 
 :ruby
-  id = "#{base.gsub(/[\[\]]/, '_')}_#{attribute}".squeeze('_')
+  id = id_for(base, attribute)
   name = "#{base}[#{attribute}][]"
   form_id = "form-#{Nanoid.generate}"
   modal_id = "modal-#{Nanoid.generate}"
diff --git a/app/views/posts/attributes/_new_predefined_array.haml b/app/views/posts/attributes/_new_predefined_array.haml
index 218a2cc2..36f1ae2f 100644
--- a/app/views/posts/attributes/_new_predefined_array.haml
+++ b/app/views/posts/attributes/_new_predefined_array.haml
@@ -3,8 +3,7 @@
   guardar, pero no se pueden agregar nuevos.
 
 :ruby
-  # @todo Convertir en un helper
-  id = "#{base.gsub(/[\[\]]/, '_')}_#{attribute}".squeeze('_')
+  id = id_for(base, attribute)
   name = "#{base}[#{attribute}][]"
   form_id = "form-#{Nanoid.generate}"