code: function _updateMergedCells(tableData, startRowIndex, startColIndex, rowspan, colspan) {
    const limitRowIndex = startRowIndex + rowspan;
    const limitColIndex = startColIndex + colspan;
    const colRange = util.range(startColIndex, limitColIndex);
  
    util.range(startRowIndex, limitRowIndex).forEach(rowIndex => {
      const rowData = tableData[rowIndex];
      const startIndex = (rowIndex === startRowIndex) ? 1 : 0;
  
      colRange.slice(startIndex).forEach(colIndex => {
        rowData[colIndex] = dataHandler.createBasicCell(rowIndex, colIndex, rowData[colIndex].nodeName);
      });
    });
  }
docs: Update merged cell data to basic cell data.
  @param {Array.<Array.<object>>} tableData - table data
  @param {number} startRowIndex - start row index
  @param {number} startColIndex - start col index
  @param {number} rowspan - rowspan property of merger cell
  @param {number} colspan - colspan property of merger cell
  @private