JSFiddle - React, Tailwind, and code Playground

HTML

<div>    
    <a href="/link1">link 1 (without the class- should stay)</a>
</div>
<div class="testdiv">
    <a href="/link2">link 2</a>
</div>
<div class="testdiv">
    <a href="/link3">link 3 (should stay)</a>
</div>
<div class="testdiv">
    <a href="/link4">link 4</a>
</div>

JavaScript

$('div.testdiv:not(:has(a[href="\\/link3"]))').fadeOut();