code: function createUrlTree(route, urlTree, commands, queryParams, fragment) {
      if (commands.length === 0) {
          return tree(urlTree.root, urlTree.root, urlTree, queryParams, fragment);
      }
      var /** @type {?} */ nav = computeNavigation(commands);
      if (nav.toRoot()) {
          return tree(urlTree.root, new __WEBPACK_IMPORTED_MODULE_1__url_tree__["c" /* UrlSegmentGroup */]([], {}), urlTree, queryParams, fragment);
      }
      var /** @type {?} */ startingPosition = findStartingPosition(nav, urlTree, route);
      var /** @type {?} */ segmentGroup = startingPosition.processChildren ?
          updateSegmentGroupChildren(startingPosition.segmentGroup, startingPosition.index, nav.commands) :
          updateSegmentGroup(startingPosition.segmentGroup, startingPosition.index, nav.commands);
      return tree(startingPosition.segmentGroup, segmentGroup, urlTree, queryParams, fragment);
  }
docs: @license
  Copyright Google Inc. All Rights Reserved.
  
  Use of this source code is governed by an MIT-style license that can be
  found in the LICENSE file at https://angular.io/license
   
  @param {?} route
  @param {?} urlTree
  @param {?} commands
  @param {?} queryParams
  @param {?} fragment
  @return {?}