diff --git a/js/src/dropdown.js b/js/src/dropdown.js
index f947d2aa11..0d06af5b51 100644
--- a/js/src/dropdown.js
+++ b/js/src/dropdown.js
@@ -250,7 +250,7 @@ const Dropdown = (($) => {
         index++
       }
 
-      if (!~index) {
+      if (index < 0) {
         index = 0
       }