code: function _getViewSequenceAtIndex(index, startViewSequence) {
          if (this._viewSequence.getAtIndex) {
              return this._viewSequence.getAtIndex(index, startViewSequence);
          }
          var viewSequence = startViewSequence || this._viewSequence;
          var i = viewSequence ? viewSequence.getIndex() : index;
          if (index > i) {
              while (viewSequence) {
                  viewSequence = viewSequence.getNext();
                  if (!viewSequence) {
                      return undefined;
                  }
                  i = viewSequence.getIndex();
                  if (i === index) {
                      return viewSequence;
                  }
                  else if (index < i) {
                      return undefined;
                  }
              }
          }
          else if (index < i) {
              while (viewSequence) {
                  viewSequence = viewSequence.getPrevious();
                  if (!viewSequence) {
                      return undefined;
                  }
                  i = viewSequence.getIndex();
                  if (i === index) {
                      return viewSequence;
                  }
                  else if (index > i) {
                      return undefined;
                  }
              }
          }
          return viewSequence;
      }
docs: Helper function for finding the view-sequence node at the given position.