import type { Either } from './either.ts';
/**
 * String representation of a locale.
 */
export type Locale = string | `${string}-${string}` | `${string}-${string}-${string}`;
/**
 * @deprecated Use Locale instead
 */
export type LocaleString = Locale;
/**
 * Object representation of a locale.
 */
export type LocaleObject = {
    language: string;
    script?: string;
    region?: string;
};
export type LanguageDirection = 'ltr' | 'rtl';
/**
 * Verify that `tag` is a valid locale code and all parts of it is in our lists of supported values.
 */
export declare const isSupportedLocale: (tag: Locale) => boolean;
/**
 * Determine if `tag` is part of our standard locales.
 */
export declare const isStandardLocale: (tag: Locale) => boolean;
/**
 * Turn LocaleObject into LocaleString.
 */
export declare const stringifyLocale: (obj: LocaleObject) => Locale;
/**
 * Parse locale string into object.
 *
 * @throws {RangeError} If locale is structurally invalid or values are not in our supported values
 */
export declare const parseLocale: (tag: Locale) => Either<string, LocaleObject>;
export declare const normalizeLocale: (tag: Locale) => string | null;
export declare const getLocaleDirection: (tag: Locale) => LanguageDirection | null;