diff --git a/src/modules/codePreviews.js b/src/modules/codePreviews.js
index 9442ce5..7ccca9c 100644
--- a/src/modules/codePreviews.js
+++ b/src/modules/codePreviews.js
@@ -39,7 +39,8 @@ async function processFile(
   const urlObj = new URL(link);
 
   let fileName = decodeURIComponent(urlObj.pathname).substring(
-    link.lastIndexOf("/") + 1
+    urlObj.pathname.lastIndexOf("/") + 1,
+    urlObj.pathname.length
   );
   const fileType =
     fileName.lastIndexOf(".") == -1