diff --git a/lisp/progmodes/js.el b/lisp/progmodes/js.el
index 3e789218fde..edb77db9bfe 100644
--- a/lisp/progmodes/js.el
+++ b/lisp/progmodes/js.el
@@ -3961,7 +3961,7 @@ See `treesit-thing-settings' for more information.")
     (treesit-major-mode-setup)
 
     (add-to-list 'auto-mode-alist
-                 '("\\(\\.js[mx]\\|\\.har\\)\\'" . js-ts-mode))))
+                 '("\\(\\.js[mx]?\\|\\.har\\)\\'" . js-ts-mode))))
 
 (derived-mode-add-parents 'js-ts-mode '(js-mode))