text: /**
   * File navigation.js.
   *
   * Handles toggling the navigation menu for small screens and enables TAB key
   * navigation support for dropdown menus.
   */
  ( function() {
      const siteNavigation = document.getElementById( 'site-navigation' );
  
      // Return early if the navigation don't exist.
      if ( ! siteNavigation ) {
          return;
      }
  
      const button = siteNavigation.getElementsByTagName( 'button' )[ 0 ];
  
      // Return early if the button don't exist.
      if ( 'undefined' === typeof button ) {
          return;
      }
  
      const menu = siteNavigation.getElementsByTagName( 'ul' )[ 0 ];
  
      // Hide menu toggle button if menu is empty and return early.
      if ( 'undefined' === typeof menu ) {
          button.style.display = 'none';
          return;
      }
  
      if ( ! menu.classList.contains( 'nav-menu' ) ) {
          menu.classList.add( 'nav-menu' );
      }
  
      // Toggle the .toggled class and the aria-expanded value each time the button is clicked.
      button.addEventListener( 'click', function() {
          siteNavigation.classList.toggle( 'toggled' );
  
          if ( button.getAttribute( 'aria-expanded' ) === 'true' ) {
              button.setAttribute( 'aria-expanded', 'false' );
          } else {
              button.setAttribute( 'aria-expanded', 'true' );
          }
      });
  
      // Remove the .toggled class and set aria-expanded to false when the user clicks outside the navigation.
      document.addEventListener( 'click', function( event ) {
          const isClickInside = siteNavigation.contains( event.target );
  
          if ( ! isClickInside ) {
              siteNavigation.classList.remove( 'toggled' );
              button.setAttribute( 'aria-expanded', 'false' );
          }
      });
  
      // Get all the link elements within the menu.
      const links = menu.getElementsByTagName( 'a' );
  
      // Get all the link elements with children within the menu.
      const linksWithChildren = menu.querySelectorAll( '.menu-item-has-children > a, .page_item_has_children > a' );
  
      // Toggle focus each time a menu link is focused or blurred.
      for ( const link of links ) {
          link.addEventListener( 'focus', toggleFocus, true );
          link.addEventListener( 'blur', toggleFocus, true );
      }
  
      // Toggle focus each time a menu link with children receive a touch event.
      for ( const link of linksWithChildren ) {
          link.addEventListener( 'touchstart', toggleFocus, false );
      }
  
      /**
       * Sets or removes .focus class on an element.
       */
      function toggleFocus() {
          if ( event.type === 'focus' || event.type === 'blur' ) {
              let self = this;
              // Move up through the ancestors of the current link until we hit .nav-menu.
              while ( ! self.classList.contains( 'nav-menu' ) ) {
                  // On li elements toggle the class .focus.
                  if ( 'li' === self.tagName.toLowerCase() ) {
                      self.classList.toggle( 'focus' );
                  }
                  self = self.parentNode;
              }
          }
  
          if ( event.type === 'touchstart' ) {
              const menuItem = this.parentNode;
              event.preventDefault();
              for ( const link of menuItem.parentNode.children ) {
                  if ( menuItem !== link ) {
                      link.classList.remove( 'focus' );
                  }
              }
              menuItem.classList.toggle( 'focus' );
          }
      }
  })();
  