1 files changed, 26 insertions, 0 deletions
diff --git a/lib/banzai/filter/inline_diff_filter.rb b/lib/banzai/filter/inline_diff_filter.rb
new file mode 100644
index 00000000000..beb21b19ab3
--- /dev/null
+++ b/lib/banzai/filter/inline_diff_filter.rb
@@ -0,0 +1,26 @@
+module Banzai
+  module Filter
+    class InlineDiffFilter < HTML::Pipeline::Filter
+      IGNORED_ANCESTOR_TAGS = %w(pre code tt).to_set
+
+      def call
+        search_text_nodes(doc).each do |node|
+          next if has_ancestor?(node, IGNORED_ANCESTOR_TAGS)
+
+          content = node.to_html
+          html_content = inline_diff_filter(content)
+
+          next if content == html_content
+
+          node.replace(html_content)
+        end
+        doc
+      end
+
+      def inline_diff_filter(text)
+        html_content = text.gsub(/(?:\[\-(.*?)\-\]|\{\-(.*?)\-\})/, '<span class="idiff left right deletion">\1\2</span>')
+        html_content.gsub(/(?:\[\+(.*?)\+\]|\{\+(.*?)\+\})/, '<span class="idiff left right addition">\1\2</span>')
+      end
+    end
+  end
+end