how to style header of exported file using excelJs

Question

How can I custom style like border,color, width etc, of creating header in excelJs ?

I can style the rows of the sheet but not the header

  fDay = days[0].charAt(0)
  sDay = days[1].charAt(0)
  sheet.columns = [
    {header: 'Num', key: 'id'},
    {header: 'Nom prenom', key: 'name'},
    {header: 'Date de naissance', key: 'birthday'},
    {header: fDay+'1', key: fDay+'1', style: {border: 'thin'}},
    {header: sDay+'1', key: sDay+'1'},
    {header: fDay+'2', key: fDay+'2'},
    {header: sDay+'2', key: sDay+'2'},
    {header: fDay+'3', key: fDay+'3'},
    {header: sDay+'3', key: sDay+'3'},
    {header: fDay+'4', key: fDay+'4'},
    {header: sDay+'4', key: sDay+'4'},
    {header: fDay+'5', key: fDay+'5'},
    {header: sDay+'5', key: sDay+'5'},
  ]
  $.each(dataPlayers, (index, player)=>{
    row = sheet.addRow({id: player.id, name: player.Prenom+' '+player.Nom, birthday: getShortDate(player.DateNaissance)})
    row.eachCell(function(cell) {
         cell.border = {
           top: {style:'thin'},
           left: {style:'thin'},
           bottom: {style:'thin'},
           right: {style:'thin'}
         };
       })
  })

the result is like this

Answer 1

So, the way that I found is to create all the rows and then iterate each cell of each row to apply a style on it or on the row it self :

sheet.eachRow({ includeEmpty: true }, function(row, rowNumber){
  row.eachCell(function(cell, colNumber){
   cell.font = {
     name: 'Arial',
     family: 2,
     bold: false,
     size: 10,
   };
   cell.alignment = {
     vertical: 'middle', horizontal: 'center'
   };
   if (rowNumber <= 10) {
     row.height = 20;
     cell.font = {
       bold: true,
     };
    }
    if (rowNumber >= 10) {
     for (var i = 1; i < 14; i++) {
       if (rowNumber == 10) {
         row.getCell(i).fill = {
           type: 'pattern',
           pattern:'solid',
           fgColor:{argb:'C7C7C7'}
         };
       }
       row.getCell(i).border = {
       top: {style:'thin'},
       left: {style:'thin'},
       bottom: {style:'thin'},
       right: {style:'thin'}
     };
   }
  }
 });
});

using the documentation of excelJS to use the style properties