/* ============================================================================
   ROUTE LOCALE
   ----------------------------------------------------------------------------
   `:lang` is already validated by the locale layout - an unknown segment 404s
   before a page loader ever runs - so this only narrows `string` to `Locale`
   for the type system, with the default locale as an unreachable fallback.
   ========================================================================= */

import { DEFAULT_LOCALE, isLocale, type Locale } from "~/i18n";

export function routeLocale(params: { readonly lang?: string }): Locale {
  return isLocale(params.lang) ? params.lang : DEFAULT_LOCALE;
}