JSFiddle - React, Tailwind, and code Playground
HTML
<div id="foo">@ericafustero Why thank you. Your work looks awesome by the way! @treemelody</div>
CSS
.s{ color: red; }
JavaScript
$(function(){
$('#foo').html( function(){return $(this).html().replace(/(@\w+)/g, "<span class='s'>$1</span>")})
})