code: function getStartEndRowsFromBoardSize(boardSize) {
      const endRow = boardSize.y - 1;
      return {
          white: getStartEndRow(endRow, false),
          black: getStartEndRow(endRow, true)
      };
  }
docs: Takes a boardSize and return START and END rows for WHITE and BLACK.
  
  returns { white:{startRow, endRow}, black:{startRow, endRow} }