JSFiddle - React, Tailwind, and code Playground

HTML

<div class="table-cont">
<div class="table-header">
    <table>
        <tbody>
            <tr>
                <td>Width 1</td>
                <td>Width 2</td>
                <td>Width 3</td>
                <td>Width 4</td>
                <td>Width 5</td>
                <td>Width 6</td>
            </tr>
        </tbody>
    </table>
</div>
<div class="table-body">
    <table>
        <tbody>
            <tr>
                <td>Width 1</td>
                <td>Width 2</td>
                <td>Width 3</td>
                <td>Width 4</td>
                <td>Width 5</td>
                <td>Width 6</td>
            </tr>
        </tbody>
    </table>
</div>
</div>

JavaScript

var tableHeader = $('.table-header').children('table').outerWidth(true);
var tableWidth = $('.table-header table tr td').width();
alert(tableWidth);
$('.table-body table tr td').each(function(){
   $(this).append(' '+tableWidth);
});