JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdn.datatables.net/1.10.5/js/jquery.dataTables.min.js"></script>
<link rel="stylesheet" href="//cdn.datatables.net/1.10.5/css/jquery.dataTables.min.css">
<!--
uncomment this table and all will return correctly
<table id="t3"></table>  -->
t1 is dt: <span id="s1"></span>
t2 is dt: <span id="s2"></span>
<table id="t1" style="background-color: red;">
    <thead>
        <tr><th>table1</th></tr>
    </thead>
    <tbody>
        <tr><td>a</td></tr>
        <tr><td>b</td></tr>
        <tr><td>c</td></tr>
    </tbody>
</table>
<hr />
<table id="t2" style="background-color: blue;">
    <thead>
        <tr><th>table2</th></tr>
    </thead>
    <tbody>
        <tr><td>a</td></tr>
        <tr><td>b</td></tr>
        <tr><td>c</td></tr>
    </tbody>
</table>
<table id="t4"><tr><td>table5</td></tr></table>

t1 is dt after making t2 a databale: <strong><span id="s3"></span></strong> (this should be false)<br />
t2 is dt after making t2 a databale: <span id="s4"></span><br />
t4 is dt after making t2 a databale: <span id="s5"></span>

JavaScript

$('#s1').text($.fn.DataTable.fnIsDataTable('#t1'));
$('#s2').text($.fn.DataTable.fnIsDataTable('#t2'));
$('#t2').dataTable();

$('#s3').text($.fn.DataTable.fnIsDataTable('#t1'));
$('#s4').text($.fn.DataTable.fnIsDataTable('#t2'));
$('#s5').text($.fn.DataTable.fnIsDataTable('#t4'));