Fix TypeError when Bootstrap is included in `head` (#32024)

* extend jquery after domContentLoaded event is fired

* add unittest for util onDOMContentLoaded

* wait for trigger jquery event after domContentLoaded

* remove domcontentready from eventHandler

* move istanbul ignore statements to correct line

Co-authored-by: XhmikosR <[email protected]>

1 files changed, 14 insertions, 11 deletions

diff --git a/js/src/scrollspy.js b/js/src/scrollspy.js
index d37ca923d..a0061b7e1 100644
--- a/js/src/scrollspy.js
+++ b/js/src/scrollspy.js
@@ -7,6 +7,7 @@
 
 import {
   getjQuery,
+  onDOMContentLoaded,
   getSelectorFromElement,
   getUID,
   isElement,
@@ -317,22 +318,24 @@ EventHandler.on(window, EVENT_LOAD_DATA_API, () => {
     .forEach(spy => new ScrollSpy(spy, Manipulator.getDataAttributes(spy)))
 })
 
-const $ = getjQuery()
-
 /**
  * ------------------------------------------------------------------------
  * jQuery
  * ------------------------------------------------------------------------
  */
-/* istanbul ignore if */
-if ($) {
-  const JQUERY_NO_CONFLICT = $.fn[NAME]
-  $.fn[NAME] = ScrollSpy.jQueryInterface
-  $.fn[NAME].Constructor = ScrollSpy
-  $.fn[NAME].noConflict = () => {
-    $.fn[NAME] = JQUERY_NO_CONFLICT
-    return ScrollSpy.jQueryInterface
+
+onDOMContentLoaded(() => {
+  const $ = getjQuery()
+  /* istanbul ignore if */
+  if ($) {
+    const JQUERY_NO_CONFLICT = $.fn[NAME]
+    $.fn[NAME] = ScrollSpy.jQueryInterface
+    $.fn[NAME].Constructor = ScrollSpy
+    $.fn[NAME].noConflict = () => {
+      $.fn[NAME] = JQUERY_NO_CONFLICT
+      return ScrollSpy.jQueryInterface
+    }
   }
-}
+})
 
 export default ScrollSpy