JSFiddle - React, Tailwind, and code Playground

HTML

<p>
    Some (text) here
</p>
<p>
    (Foo) and {bar} or {foobar}
</p>

JavaScript

var ps = document.getElementsByTagName('p');
    foreach = Array.prototype.forEach;

foreach.call(ps, function (p) {
    var content = p.innerHTML;
    p.innerHTML = content.replace(/\{(.*?)\}|\((.*?)\)/g, function (m) {
        return '<span style="font-weight: bold;">' + m + '</span>';
    });
});