Initial Drupal 11 with DDEV setup

web/core/modules/navigation/js/toolbar-dropdown.js

@@ -0,0 +1,53 @@
+/* cspell:ignore uidom */
+((Drupal, once, { computePosition, offset, shift, flip }) => {
+  /**
+   * Attaches the dropdown behavior to all required triggers.
+   *
+   * @type {Drupal~behavior}
+   *
+   * @prop {Drupal~behaviorAttach} attach
+   *   Attaches the dropdown behavior.
+   */
+  Drupal.behaviors.dropdownInit = {
+    attach: (context) => {
+      once('dropdown-trigger', '[data-drupal-dropdown]', context).forEach(
+        (trigger) => {
+          const dropdown = trigger.nextElementSibling;
+
+          const updatePosition = () => {
+            computePosition(trigger, dropdown, {
+              strategy: 'fixed',
+              placement: trigger.dataset.drupalDropdownPosition || 'bottom',
+              middleware: [
+                flip({ padding: 16 }),
+                offset(6),
+                shift({ padding: 16 }),
+              ],
+            }).then(({ x, y }) => {
+              Object.assign(dropdown.style, {
+                left: `${x}px`,
+                top: `${y}px`,
+              });
+            });
+          };
+
+          trigger.addEventListener('click', (e) => {
+            updatePosition();
+            trigger.setAttribute(
+              'aria-expanded',
+              e.currentTarget.getAttribute('aria-expanded') === 'false',
+            );
+          });
+
+          // Event listener to close dropdown when clicking outside
+          document.addEventListener('click', (e) => {
+            const isButtonClicked = trigger.contains(e.target);
+            if (!isButtonClicked) {
+              trigger.setAttribute('aria-expanded', 'false');
+            }
+          });
+        },
+      );
+    },
+  };
+})(Drupal, once, FloatingUIDOM);