Method _handleKeyEvent

src/cdk/menu/menu-bar.ts:61–104

* Handle keyboard events for the Menu. * @param event The keyboard event to be handled.

(event: KeyboardEvent)

   * @param event The keyboard event to be handled.
   */
  _handleKeyEvent(event: KeyboardEvent) {
    const keyManager = this.keyManager;
    switch (event.keyCode) {
      case UP_ARROW:
      case DOWN_ARROW:
      case LEFT_ARROW:
      case RIGHT_ARROW:
        if (!hasModifierKey(event)) {
          const horizontalArrows = event.keyCode === LEFT_ARROW || event.keyCode === RIGHT_ARROW;
          // For a horizontal menu if the left/right keys were clicked, or a vertical menu if the
          // up/down keys were clicked: if the current menu is open, close it then focus and open the
          // next  menu.
          if (horizontalArrows) {
            event.preventDefault();

            const prevIsOpen = keyManager.activeItem?.isMenuOpen();
            keyManager.activeItem?.getMenuTrigger()?.close();

            keyManager.setFocusOrigin('keyboard');
            keyManager.onKeydown(event);
            if (prevIsOpen) {
              keyManager.activeItem?.getMenuTrigger()?.open();
            }
          }
        }
        break;

      case ESCAPE:
        if (!hasModifierKey(event)) {
          event.preventDefault();
          keyManager.activeItem?.getMenuTrigger()?.close();
        }
        break;

      case TAB:
        if (!hasModifierKey(event, 'altKey', 'metaKey', 'ctrlKey')) {
          keyManager.activeItem?.getMenuTrigger()?.close();
        }
        break;

      default:
        keyManager.onKeydown(event);
    }
  }

  /**
   * Set focus to either the current, previous or next item based on the FocusNext event, then