JSFiddle - React, Tailwind, and code Playground

HTML

<table>
	<thead>
		<tr>
			<th>Heading 1</th>
			<th>Heading 2</th>
			<th>Heading 3</th>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td>Lorem</td>
			<td>lipsum</td>
			<td>dolor</td>
		</tr>
		<tr>
			<td>Lorem</td>
			<td>lipsum</td>
			<td>dolor</td>
		</tr>
	</tbody>
</table>

JavaScript

var $th = $("thead th");
var $tr = $("tbody tr");

$tr.each(function(){
    var $td = $("td", this);
    $td.each(function(i, el){
        $(this).attr('data-attr', $th.eq(i).text());
    });
});