getPathname with dynamic route in sitemap

[MeesEgberts]

This is my sitemap.ts:

export default function sitemap(): MetadataRoute.Sitemap {
  const keys = Object.keys(routes) as Array<keyof typeof routes>;

  function getUrl(key: keyof typeof routes, locale: (typeof locales)[number]) {
    const pathname = getPathname({ locale, href: key });

    return `${host}/${locale}${pathname === '/' ? '' : pathname}`;
  }

  return keys.map((key) => ({
    url: getUrl(key, defaultLocale),
    alternates: {
      languages: Object.fromEntries(
        locales.map((locale) => [locale, getUrl(key, locale)]),
      ),
    },
  }));
}

And these are my pathnames:

export const routes = {
  "/": "/",
  "/sign-in/[[...sign-in]]": {
    nl: "/login/[[...sign-in]]",
    en: "/sign-in/[[...sign-in]]",
  },
  "/sign-up/[[...sign-up]]": {
    nl: "/registreer/[[...sign-up]]",
    en: "/sign-up/[[...sign-up]]",
  },
} satisfies Pathnames<typeof locales>;

Now when I run the command pnpm run build the sitemap should be build. But here is where I ran into an issue. It throws this error:

Template: /login/[[...sign-in]]
Params: undefined