diff --git a/frontend/files/app.js b/frontend/files/app.js
index ae1b25b..2067c13 100644
--- a/frontend/files/app.js
+++ b/frontend/files/app.js
@@ -154,7 +154,7 @@ function BookTemplate({
   <div class="bookDetails">
     <h1>${title}</h1>
     <h2>${authors}</h2>
-    <span>${[isbn10, isbn13].join(" / ")}</span><br/>
+    <span>${[isbn10, isbn13].filter((v) => v != "").join(" / ")}</span><br/>
     <span>${publisher}, ${year}</span><br/>
     ${
       series