diff --git a/_plugins/bidirectional_links_generator.rb b/_plugins/bidirectional_links_generator.rb
index 8d7b52c..70f956f 100644
--- a/_plugins/bidirectional_links_generator.rb
+++ b/_plugins/bidirectional_links_generator.rb
@@ -66,7 +66,11 @@ class BidirectionalLinksGenerator < Jekyll::Generator
   end
 
   def note_id_from_note(note)
-    note.data['title'].gsub!(/\W+/, ' ')
-    note.data['title'].delete(' ').to_i(36).to_s
+    note.data['title']
+      .dup
+      .gsub(/\W+/, ' ')
+      .delete(' ')
+      .to_i(36)
+      .to_s
   end
 end