const rowCount = 18527;
const colCount = 272;

for (let i = 1; i <= rowCount; i++) {
  const row = [];
  for (let j = 1; j <= colCount; j++) {
    row.push(Math.random());
  }
  worksheet.addRow(row);

  if (i % 33 === 1) { // Make header every 33 rows
    for (let col = 1; col <= colCount; col += 1) {
      const cell = worksheet.getCell(i, col);
      cell.font = { color: { argb: "FFFFFFFF" }, bold: true };
      cell.fill = {
        type: "pattern",
        pattern: "solid",
        fgColor: { argb: "#FFD9D9D9" },
      };
    }
  } else {
    for (let col = 1; col <= colCount; col += 1) {
      const cell = worksheet.getCell(i, col);
      cell.numFmt = '0.00;[Red]-0.00;-'
    }
  }
}