JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://cdn.datatables.net/1.10.15/css/jquery.dataTables.min.css">
<link rel="stylesheet" href="https://cdn.datatables.net/buttons/1.4.0/css/buttons.dataTables.min.css">
<script src="//code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://cdn.datatables.net/1.10.15/js/jquery.dataTables.min.js"></script>
<script src="https://cdn.datatables.net/buttons/1.4.0/js/dataTables.buttons.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jszip/3.1.3/jszip.min.js"></script>
<script src="//cdn.datatables.net/buttons/1.4.0/js/buttons.html5.min.js"></script>
<table id="example" class="display" width="100%" cellspacing="0">
        <thead>
            <tr>
                <th>Name</th>
                <th>Position</th>
                <th>Office</th>
                <th>Age</th>
                <th>Start date</th>
                <th>Salary</th>
            </tr>
        </thead>
        <tfoot>
            <tr>
                <th>Name</th>
                <th>Position</th>
                <th>Office</th>
                <th>Age</th>
                <th>Start date</th>
                <th>Salary</th>
            </tr>
        </tfoot>
        <tbody>
            <tr>
                <td>Tiger Nixon</td>
                <td>System Architect</td>
                <td>Edinburgh</td>
                <td>61</td>
                <td>2011/04/25</td>
                <td>$320,800</td>
            </tr>
            <tr>
                <td>Garrett Winters</td>
                <td>Accountant</td>
                <td>Tokyo</td>
                <td>63</td>
                <td>2011/07/25</td>
                <td>$170,750</td>
            </tr>
            <tr>
                <td>Ashton Cox</td>
                <td>Junior Technical Author</td>
                <td>San Francisco</td>
                <td>66</td>
                <td>2009/01/12</td>
                <td>$86,000</td>
            </tr>
            <tr>
                <td>Cedric...

JavaScript

$(document).ready(function() {
    $('#example').DataTable({
        dom: 'Bfrtip',
        buttons: [{
            extend: 'excelHtml5',
            customize: function(xlsx) {
                var sheet = xlsx.xl.worksheets['sheet1.xml'];
							console.log(sheet);	
							var downrows = 1;
							var clRow = $('row', sheet);
							var msg;
							//update Row
							clRow.each(function() {
							var attr = $(this).attr('r');
							var ind = parseInt(attr);
							ind = ind + downrows;
							$(this).attr("r", ind);
									});
									
							 // Update  row > c
							$('row c ', sheet).each(function() {
							var attr = $(this).attr('r');
							var pre = attr.substring(0, 1);
							var ind = parseInt(attr.substring(1, attr.length));
							ind = ind + downrows;
							$(this).attr("r", pre + ind);
							});

						function Addrow(index, data) {

						msg = '<row r="' + index + '">';
						for (var i = 0; i < data.length; i++) {
						var key = data[i].k;
						var value = data[i].v;
						msg += '<c t="inlineStr" r="' + key + index + '">';
						msg += '<is>';
						msg += '<t>' + value + '</t>';
						msg += '</is>';
						msg += '</c>';
							}
						msg += '</row>';
						
						return msg;
							}
              
             var r1 = Addrow(1, [{
					k: 'B',
					v: 'HR'
					}]);
              
             sheet.childNodes[0].childNodes[1].innerHTML = r1 + sheet.childNodes[0].childNodes[1].innerHTML; 
              
            }
        }]
    });
});