<pre class="shiki github-dark shaku"><code>type MyCapitalize&lt;T extends string&gt; = T extends `${infer P}${infer U}` ? `${Uppercase&lt;P&gt;}${U}` : T;</code></pre>

esay infer

Implement MyCapitalize<T> to capitalize strings. type A = MyCapitalize<'bfe'> // 'Bfe' > There is built-in Capitalize<T> in TypeScript, maybe you can …