JSFiddle - React, Tailwind, and code Playground
HTML
<div id="root">
</div>
JavaScript
var new_html = "foo and bar(arg)";
var bad_string = "bar\\(arg\\)";
var regex = new RegExp(bad_string, "igm");
var bad_start = new_html.search(regex);
document.getElementById('root').html(bad_start);