code: function _expandColMergedRange(tableData, tableRange, rowIndex, colIndex) {
    const rowData = tableData[rowIndex];
    const cellData = rowData[colIndex];
    const {colMergeWith} = cellData;
    let lastColMergedIndex = -1;
  
    if (util.isExisty(colMergeWith)) {
      if (colMergeWith < tableRange.start.colIndex) {
        tableRange.start.colIndex = colMergeWith;
      }
  
      lastColMergedIndex = colMergeWith + rowData[colMergeWith].colspan - 1;
    } else if (cellData.colspan > 1) {
      lastColMergedIndex = colIndex + cellData.colspan - 1;
    }
  
    if (lastColMergedIndex > tableRange.end.colIndex) {
      tableRange.end.colIndex = lastColMergedIndex;
    }
  }
docs: Expand table range by column merge properties like colspan, colMergeWith.
  @param {Array.<Array.<object>>} tableData - table data
  @param {{
  start: {rowIndex: number, colIndex: number},
  end: {rowIndex: number, colIndex: number}
  }} tableRange - table range
  @param {number} rowIndex - row index
  @param {number} colIndex - column index
  @private