<pre class="shiki github-dark shaku"><code>function classNames(...args) { let classes = []; args.forEach(arg =&gt; { if (typeof arg === 'string' || typeof arg === 'number') { classes.push(arg); } else if (Array.isArray(arg)) { classes.push(classNames(...arg)); } else if (typeof arg === 'object' &amp;&amp; arg !== null) { for (const key in arg) { if (Object.prototype.hasOwnProperty.call(arg, key) &amp;&amp; arg[key]) { classes.push(key); } } } }); return classes.join(' ');}</code></pre>