JSFiddle - React, Tailwind, and code Playground
HTML
<div id="text">
<b>paragraph</b>
<u>should be stripped</u>
<span style="color:red">should be stripped</span>
</div>
JavaScript
$('div').find('span').contents().unwrap();
<div id="text">
<b>paragraph</b>
<u>should be stripped</u>
<span style="color:red">should be stripped</span>
</div>
$('div').find('span').contents().unwrap();