/**
 * The app is translated into a few languages, one Lingui catalogue each under
 * `locales/`. This module lists them once for every reader: `lingui.config.ts`
 * extracts and compiles a catalogue per locale, the client picks one per
 * browser, and the server writes its emails in `GERBEUR_EMAIL_LOCALE`.
 *
 * @module
 */

/** Lists the locales the app is translated into. */
export const LOCALES = ["en", "fr"] as const;
/** One of the {@link LOCALES}. */
export type Locale = typeof LOCALES[number];
/** The locale the messages are written in, and the fallback for any other. */
export const SOURCE_LOCALE: Locale = "en";

/** Checks whether `value` is a {@link Locale}. */
export function isLocale(value: unknown): value is Locale {
  return typeof value === "string" &&
    (LOCALES as readonly string[]).includes(value);
}