diff --git a/js/src/dom/selector-engine.js b/js/src/dom/selector-engine.js
index af27dc3795..39f3971dca 100644
--- a/js/src/dom/selector-engine.js
+++ b/js/src/dom/selector-engine.js
@@ -79,7 +79,7 @@ const SelectorEngine = {
       'details',
       '[tabindex]',
       '[contenteditable="true"]'
-    ].map(selector => `${selector}:not([tabindex^="-"])`).join(', ')
+    ].map(selector => `${selector}:not([tabindex^="-"])`).join(',')
 
     return this.find(focusables, element).filter(el => !isDisabled(el) && isVisible(el))
   }