Added ReferenceFilter#nodes

This method returns an Array of the HTML nodes as yielded by
ReferenceFilter#each_node. The method's return value is memoized to
allow multiple calls without having to re-query the input document.

lib/banzai/filter/reference_filter.rb

@@ -80,6 +80,11 @@ module Banzai
         end
       end
 
+      # Returns an Array containing all HTML nodes.
+      def nodes
+        @nodes ||= each_node.to_a
+      end
+
       # Yields the link's URL and text whenever the node is a valid <a> tag.
       def yield_valid_link(node)
         link = CGI.unescape(node.attr('href').to_s)

spec/lib/banzai/filter/reference_filter_spec.rb

@@ -33,4 +33,13 @@ describe Banzai::Filter::ReferenceFilter, lib: true do
       expect { |b| filter.each_node(&b) }.not_to yield_control
     end
   end
+
+  describe '#nodes' do
+    it 'returns an Array of the HTML nodes' do
+      document = Nokogiri::HTML.fragment('<a href="foo">foo</a>')
+      filter = described_class.new(document, project: project)
+
+      expect(filter.nodes).to eq([document.children[0]])
+    end
+  end
 end