code: function saveTab(tabWindow, tabItem, tabNode) {
    var _tabWindow$tabItems$f3 = tabWindow.tabItems.findEntry(function (ti) {
      return ti.open && ti.openTabId === tabItem.openTabId;
    });
  
    var _tabWindow$tabItems$f4 = _slicedToArray(_tabWindow$tabItems$f3, 1);
  
    var index = _tabWindow$tabItems$f4[0];
  
  
    var updTabItem = tabItem.set('saved', true).set('savedTitle', tabNode.title).set('savedBookmarkId', tabNode.id).set('savedBookmarkIndex', tabNode.index);
  
    var updItems = tabWindow.tabItems.splice(index, 1, updTabItem);
  
    return tabWindow.set('tabItems', updItems);
  }
docs: Update a tab's saved state
  
  @param {TabWindow} tabWindow - tab window with tab that's been closed
  @param {TabItem} tabItem -- open tab that has been saved
  @param {BookmarkTreeNode} tabNode -- bookmark node for saved bookmark
  
  @return {TabWindow} tabWindow with tabItems updated to reflect saved state