/**
 * @module i18n/catalogue
 * Registry of translation files, filled by the application at startup.
 *
 * A bundler resolves import paths relative to the file that contains them, so a
 * library can never discover translation files that live in an application. The
 * application therefore hands its files to the library instead.
 *
 * @example
 * // Vite
 * import { registerCatalogue } from '@relax.js/core/i18n';
 * registerCatalogue(import.meta.glob('./locales/*\/*.json', { eager: true }));
 *
 * @example
 * // Any bundler, or no bundler at all
 * import { registerNamespace } from '@relax.js/core/i18n';
 * import shellEn from './locales/en/shell.json';
 * registerNamespace('en', 'shell', shellEn);
 */
export type TranslationMap = Record<string, string>;
/**
 * Loads a namespace the first time it is used, so translations for locales
 * nobody selects stay out of the initial download.
 */
export type NamespaceLoader = () => Promise<TranslationMap | {
    default: TranslationMap;
}>;
/**
 * A namespace given either as ready messages or as a loader that fetches them.
 */
export type NamespaceSource = TranslationMap | NamespaceLoader;
/**
 * Reduces `en-US` to `en`, so a browser language matches a translation folder.
 */
export declare function normalizeLocale(locale: string): string;
/**
 * Adds a single namespace to the catalogue.
 *
 * Registering the same locale and namespace twice replaces the previous entry,
 * which lets an application override a built-in namespace such as `r-validation`.
 *
 * @param locale - Locale code, normalized the same way as `setLocale()`
 * @param namespace - Namespace name used in front of the colon in `t('shell:title')`
 * @param source - The messages, or a function that loads them on first use
 *
 * @example
 * import shellEn from './locales/en/shell.json';
 * registerNamespace('en', 'shell', shellEn);
 *
 * @example
 * registerNamespace('sv', 'shell', () => import('./locales/sv/shell.json'));
 */
export declare function registerNamespace(locale: string, namespace: string, source: NamespaceSource): void;
/**
 * Adds every namespace in a path-keyed record, so a whole `locales/` folder is
 * registered in one call.
 *
 * The locale and namespace are read from the last two segments of each key, so
 * `./locales/en/shell.json` becomes locale `en` and namespace `shell`. Values may
 * be the messages, a module with the messages as its default export, or a
 * function returning either. That covers Vite's eager and lazy `import.meta.glob`,
 * webpack's `require.context`, and a plain object written by hand.
 *
 * @param modules - Record keyed by file path
 *
 * @example
 * // Vite, everything in the first download
 * registerCatalogue(import.meta.glob('./locales/*\/*.json', { eager: true }));
 *
 * @example
 * // Vite, each locale downloaded when it is first selected
 * registerCatalogue(import.meta.glob('./locales/*\/*.json'));
 *
 * @example
 * // No bundler
 * registerCatalogue({
 *     './locales/en/shell.json': { title: 'Dashboard' },
 *     './locales/sv/shell.json': { title: 'Instrumentpanel' },
 * });
 */
export declare function registerCatalogue(modules: Record<string, unknown>): void;
/**
 * Returns the messages for a namespace, or `undefined` when it was never registered.
 *
 * Rejects when a registered loader fails, so a network error is reported rather
 * than mistaken for a namespace nobody registered.
 */
export declare function resolveNamespace(locale: string, namespace: string): Promise<TranslationMap | undefined>;