Update/fix active-link.js (see core issues #3464340 and #3038523).

Closes #3515452

assets/js/misc/active-link-trail.js

+/**
+ * @file
+ * Attaches behaviors for Drupal's active trail link marking.
+ */
+
+((Drupal, drupalSettings) => {
+  const activeClass = 'active';
+
+  /**
+   * Append active class.
+   *
+   * The link is only active if it has data-drupal-active-trail=true.
+   *
+   * Does not discriminate based on element type, so allows you to set the
+   * active class on any element: a, li…
+   *
+   * @type {Drupal~behavior}
+   */
+  Drupal.behaviors.ui_suite_bootstrap_activeTrailLinks = {
+    attach(context) {
+      // Start by finding all potentially active links.
+      const { path } = drupalSettings;
+      const queryString = JSON.stringify(path.currentQuery);
+      const querySelector = queryString
+        ? `[data-drupal-link-query="${CSS.escape(queryString)}"]`
+        : ':not([data-drupal-link-query])';
+      const originalSelectors = [`[data-drupal-active-trail=true]`];
+      let selectors;
+
+      // Add language filtering.
+      selectors = [].concat(
+        // Links without any hreflang attributes (most of them).
+        originalSelectors.map((selector) => `${selector}:not([hreflang])`),
+        // Links with hreflang equals to the current language.
+        originalSelectors.map(
+          (selector) => `${selector}[hreflang="${path.currentLanguage}"]`,
+        ),
+      );
+
+      // Add query string selector for pagers, exposed filters.
+      selectors = selectors.map((current) => current + querySelector);
+
+      // Query the DOM.
+      const activeLinks = context.querySelectorAll(selectors.join(','));
+      const il = activeLinks.length;
+      for (let i = 0; i < il; i++) {
+        activeLinks[i].classList.add(activeClass);
+      }
+    },
+    detach(context, settings, trigger) {
+      if (trigger === 'unload') {
+        const activeLinks = context.querySelectorAll(
+          `[data-drupal-active-trail=true]`,
+        );
+        const il = activeLinks.length;
+        for (let i = 0; i < il; i++) {
+          activeLinks[i].classList.remove(activeClass);
+        }
+      }
+    },
+  };
+})(Drupal, drupalSettings);