Can do the hard ones czech names like ""Řehoř" -> "Řehoři" and names consisting of two first name like "Jaroslav Jan" -> "Jaroslave Jane".

Library also support surnames like "Klaus" -> "Klausi".

And both of them together like "Petr Klaus" -> "Petře Klausi".

You can install the package via pnpm:

pnpm install vocative-cz

or if you are still using npm:

npm install vocative-cz

import { vocative } from "vocative-cz";

console.log(vocative("Řehoř")); // Řehoři
console.log(vocative("Eva")); // Evo
console.log(vocative("Petr Klaus")); // Petře Klausi
console.log(vocative("Jaroslav Jan")); // Jaroslave Jane