How to style a XLSX file using exceljs and node.js streams?

Formatting and styling works in a typical situation

  const workbook = new ExcelJS.Workbook();
  const worksheet = workbook.addWorksheet('My Sheet');

  // Add headers
  worksheet.addRow(["Column 1", "Column 2", "Column 3", "Column 4"]).eachCell((cell) => {
    cell.fill = {
      type: 'pattern',
      pattern: 'solid',
      fgColor: { argb: '1a5896' }, // Yellow color
    };
    cell.font = { bold: true, color: { argb: 'F8F9FA' }, }; // Make text bold
  });

However while streaming a file to a HTTP response I am unable to change styling

  const workbook = new exceljs.stream.xlsx.WorkbookWriter({stream: response});
  const worksheet = workbook.addWorksheet('My Sheet');
  
  // Add headers
  worksheet.addRow(["Column 1", "Column 2", "Column 3", "Column 4"]).eachCell((cell) => {
    cell.fill = {
      type: 'pattern',
      pattern: 'solid',
      fgColor: { argb: '1a5896' }, // Yellow color
    };
    cell.font = { bold: true, color: { argb: 'F8F9FA' }, }; // Make text bold
  });

How can I change style of cells while streaming?

By default you can't add style information due to some performance overhead, you can override this behaviour by specifying useStyles set to true.

  const workbook = new exceljs.stream.xlsx.WorkbookWriter(
    { 
      stream: response,
      useStyles: true, // set this <-
    }
  );
  const worksheet = workbook.addWorksheet('My Sheet');
  
  // Add headers
  worksheet.addRow(["Column 1", "Column 2", "Column 3", "Column 4"]).eachCell((cell) => {
    cell.fill = {
      type: 'pattern',
      pattern: 'solid',
      fgColor: { argb: '1a5896' }, // Yellow color
    };
    cell.font = { bold: true, color: { argb: 'F8F9FA' }, }; // Make text bold
  });