JSFiddle - React, Tailwind, and code Playground

HTML

<p>My brother is great.</p>
<p>http://www.youtube.com/watch?v=ef0wk8QoA34</p>
<a href="http://www.youtube.com/watch?v=ef0wk8QoA34">http://www.youtube.com/watch?v=ef0wk8QoA34</a>

JavaScript

$('a').filter(function() {
    return $(this).text().match(/^(?:https?:\/\/)?(?:www\.)?youtube\.com\/watch\?(?=.*v=((\w|-){11}))(?:\S+)?$/g);
}).each(function() {
    $(this).text($(this).text().replace(/youtube.com/g, 'video'));
});