All functions are available in the main module. You can import them like this:
import { getInternationalDays } from 'international-days-cs';
// get all international days for 01-01-2024
const days = getInternationalDays(new Date(2024, 0, 1));
console.log(days);
// or you can get all days as string
console.log(
days.map(day => `${day.icon} ${day.name}`).join('\n')
);