drupal/core/misc/tabbingmanager.js

/**
* DO NOT EDIT THIS FILE.
* See the following change record for more information,
* https://www.drupal.org/node/2815083
* @preserve
**/

(function ($, Drupal, {
  tabbable,
  isTabbable
}) {
  function TabbingManager() {
    this.stack = [];
  }

  function TabbingContext(options) {
    $.extend(this, {
      level: null,
      $tabbableElements: $(),
      $disabledElements: $(),
      released: false,
      active: false,
      trapFocus: false
    }, options);
  }

  $.extend(TabbingManager.prototype, {
    constrain(elements, {
      trapFocus = false
    } = {}) {
      const il = this.stack.length;

      for (let i = 0; i < il; i++) {
        this.stack[i].deactivate();
      }

      let tabbableElements = [];
      $(elements).each((index, rootElement) => {
        tabbableElements = [...tabbableElements, ...tabbable(rootElement)];

        if (isTabbable(rootElement)) {
          tabbableElements = [...tabbableElements, rootElement];
        }
      });
      const tabbingContext = new TabbingContext({
        level: this.stack.length,
        $tabbableElements: $(tabbableElements),
        trapFocus
      });
      this.stack.push(tabbingContext);
      tabbingContext.activate();
      $(document).trigger('drupalTabbingConstrained', tabbingContext);
      return tabbingContext;
    },

    release() {
      let toActivate = this.stack.length - 1;

      while (toActivate >= 0 && this.stack[toActivate].released) {
        toActivate--;
      }

      this.stack.splice(toActivate + 1);

      if (toActivate >= 0) {
        this.stack[toActivate].activate();
      }
    },

    activate(tabbingContext) {
      const $set = tabbingContext.$tabbableElements;
      const level = tabbingContext.level;
      const $disabledSet = $(tabbable(document.body)).not($set);
      tabbingContext.$disabledElements = $disabledSet;
      const il = $disabledSet.length;

      for (let i = 0; i < il; i++) {
        this.recordTabindex($disabledSet.eq(i), level);
      }

      $disabledSet.prop('tabindex', -1).prop('autofocus', false);
      let $hasFocus = $set.filter('[autofocus]').eq(-1);

      if ($hasFocus.length === 0) {
        $hasFocus = $set.eq(0);
      }

      $hasFocus.trigger('focus');

      if ($set.length && tabbingContext.trapFocus) {
        $set.last().on('keydown.focus-trap', event => {
          if (event.key === 'Tab' && !event.shiftKey) {
            event.preventDefault();
            $set.first().focus();
          }
        });
        $set.first().on('keydown.focus-trap', event => {
          if (event.key === 'Tab' && event.shiftKey) {
            event.preventDefault();
            $set.last().focus();
          }
        });
      }
    },

    deactivate(tabbingContext) {
      const $set = tabbingContext.$disabledElements;
      const level = tabbingContext.level;
      const il = $set.length;
      tabbingContext.$tabbableElements.first().off('keydown.focus-trap');
      tabbingContext.$tabbableElements.last().off('keydown.focus-trap');

      for (let i = 0; i < il; i++) {
        this.restoreTabindex($set.eq(i), level);
      }
    },

    recordTabindex($el, level) {
      const tabInfo = $el.data('drupalOriginalTabIndices') || {};
      tabInfo[level] = {
        tabindex: $el[0].getAttribute('tabindex'),
        autofocus: $el[0].hasAttribute('autofocus')
      };
      $el.data('drupalOriginalTabIndices', tabInfo);
    },

    restoreTabindex($el, level) {
      const tabInfo = $el.data('drupalOriginalTabIndices');

      if (tabInfo && tabInfo[level]) {
        const data = tabInfo[level];

        if (data.tabindex) {
          $el[0].setAttribute('tabindex', data.tabindex);
        } else {
          $el[0].removeAttribute('tabindex');
        }

        if (data.autofocus) {
          $el[0].setAttribute('autofocus', 'autofocus');
        }

        if (level === 0) {
          $el.removeData('drupalOriginalTabIndices');
        } else {
          let levelToDelete = level;

          while (tabInfo.hasOwnProperty(levelToDelete)) {
            delete tabInfo[levelToDelete];
            levelToDelete++;
          }

          $el.data('drupalOriginalTabIndices', tabInfo);
        }
      }
    }

  });
  $.extend(TabbingContext.prototype, {
    release() {
      if (!this.released) {
        this.deactivate();
        this.released = true;
        Drupal.tabbingManager.release(this);
        $(document).trigger('drupalTabbingContextReleased', this);
      }
    },

    activate() {
      if (!this.active && !this.released) {
        this.active = true;
        Drupal.tabbingManager.activate(this);
        $(document).trigger('drupalTabbingContextActivated', this);
      }
    },

    deactivate() {
      if (this.active) {
        this.active = false;
        Drupal.tabbingManager.deactivate(this);
        $(document).trigger('drupalTabbingContextDeactivated', this);
      }
    }

  });

  if (Drupal.tabbingManager) {
    return;
  }

  Drupal.tabbingManager = new TabbingManager();
})(jQuery, Drupal, window.tabbable);