Added grouped_options_for_select helper method for wrapping option ta…

…gs in optgroups. [#977 state:resolved]

Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

actionpack/CHANGELOG

@@ -1,5 +1,7 @@
 *2.3.0 [Edge]*
 
+* Added grouped_options_for_select helper method for wrapping option tags in optgroups. #977 [Jon Crawford]
+
 * Implement HTTP Digest authentication. #1230 [Gregg Kellogg, Pratik Naik] Example :
 
   class DummyDigestController < ActionController::Base

actionpack/lib/action_view/helpers/form_options_helper.rb

@@ -277,6 +277,62 @@ def option_groups_from_collection_for_select(collection, group_method, group_lab
         end
       end
 
+      # Returns a string of <tt><option></tt> tags, like <tt>options_for_select</tt>, but
+      # wraps them with <tt><optgroup></tt> tags.
+      #
+      # Parameters:
+      # * +grouped_options+ - Accepts a nested array or hash of strings.  The first value serves as the
+      #   <tt><optgroup></tt> label while the second value must be an array of options. The second value can be a
+      #   nested array of text-value pairs. See <tt>options_for_select</tt> for more info.
+      #    Ex. ["North America",[["United States","US"],["Canada","CA"]]]
+      # * +selected_key+ - A value equal to the +value+ attribute for one of the <tt><option></tt> tags,
+      #   which will have the +selected+ attribute set. Note: It is possible for this value to match multiple options
+      #   as you might have the same option in multiple groups.  Each will then get <tt>selected="selected"</tt>.
+      # * +prompt+ - set to true or a prompt string. When the select element doesn’t have a value yet, this
+      #   prepends an option with a generic prompt — "Please select" — or the given prompt string.
+      #
+      # Sample usage (Array):
+      #   grouped_options = [
+      #    ['North America',
+      #      [['United States','US'],'Canada']],
+      #    ['Europe',
+      #      ['Denmark','Germany','France']]
+      #   ]
+      #   grouped_options_for_select(grouped_options)
+      #
+      # Sample usage (Hash):
+      #   grouped_options = {
+      #    'North America' => [['United States','US], 'Canada'],
+      #    'Europe' => ['Denmark','Germany','France']
+      #   }
+      #   grouped_options_for_select(grouped_options)
+      #
+      # Possible output:
+      #   <optgroup label="Europe">
+      #     <option value="Denmark">Denmark</option>
+      #     <option value="Germany">Germany</option>
+      #     <option value="France">France</option>
+      #   </optgroup>
+      #   <optgroup label="North America">
+      #     <option value="US">United States</option>
+      #     <option value="Canada">Canada</option>
+      #   </optgroup>
+      #
+      # <b>Note:</b> Only the <tt><optgroup></tt> and <tt><option></tt> tags are returned, so you still have to
+      # wrap the output in an appropriate <tt><select></tt> tag.
+      def grouped_options_for_select(grouped_options, selected_key = nil, prompt = nil)
+        body = ''
+        body << content_tag(:option, prompt, :value => "") if prompt
+
+        grouped_options = grouped_options.sort if grouped_options.is_a?(Hash)
+
+        grouped_options.each do |group|
+          body << content_tag(:optgroup, options_for_select(group[1], selected_key), :label => group[0])
+        end
+
+        body
+      end
+
       # Returns a string of option tags for pretty much any time zone in the
       # world. Supply a TimeZone name as +selected+ to have it marked as the
       # selected option tag. You can also supply an array of TimeZone objects

actionpack/test/template/form_options_helper_test.rb

@@ -143,6 +143,32 @@ def test_option_groups_from_collection_for_select
       )
     end
 
+    def test_grouped_options_for_select_with_array
+      assert_dom_equal(
+        "<optgroup label=\"North America\"><option value=\"US\">United States</option>\n<option value=\"Canada\">Canada</option></optgroup><optgroup label=\"Europe\"><option value=\"GB\">Great Britain</option>\n<option value=\"Germany\">Germany</option></optgroup>",
+        grouped_options_for_select([
+           ["North America",
+               [['United States','US'],"Canada"]],
+           ["Europe",
+               [["Great Britain","GB"], "Germany"]]
+         ])
+      )
+    end
+
+    def test_grouped_options_for_select_with_selected_and_prompt
+      assert_dom_equal(
+          "<option value=\"\">Choose a product...</option><optgroup label=\"Hats\"><option value=\"Baseball Cap\">Baseball Cap</option>\n<option selected=\"selected\" value=\"Cowboy Hat\">Cowboy Hat</option></optgroup>",
+          grouped_options_for_select([["Hats", ["Baseball Cap","Cowboy Hat"]]], "Cowboy Hat", "Choose a product...")
+      )
+    end
+
+    def test_optgroups_with_with_options_with_hash
+      assert_dom_equal(
+         "<optgroup label=\"Europe\"><option value=\"Denmark\">Denmark</option>\n<option value=\"Germany\">Germany</option></optgroup><optgroup label=\"North America\"><option value=\"United States\">United States</option>\n<option value=\"Canada\">Canada</option></optgroup>",
+         grouped_options_for_select({'North America' => ['United States','Canada'], 'Europe' => ['Denmark','Germany']})
+      )
+    end
+
     def test_time_zone_options_no_parms
       opts = time_zone_options_for_select
       assert_dom_equal "<option value=\"A\">A</option>\n" +