JSFiddle - React, Tailwind, and code Playground
HTML
<table border="2">
<tr><td>one</td><td>two</td></tr>
<tr><td>one</td><td>two</td></tr>
<tr><td colspan="2" id="new" >add new</td></tr>
</table>
JavaScript
$('#new').click(function(){
$("<tr><td>one</td><td>two</td></tr>").insertBefore($(this).parent());
})