JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://getfirebug.com/firebug-lite-debug.js"></script>

JavaScript

d = '00:10:01'
if(/\d{2}:\d{2}:\d{2}/.test(d)) {
    console.log('ok');
}
else {
    console.log('not ok');
}