import { DateFormatOptions, Locale } from './transloco-locale.types';
export declare const ISO8601_DATE_REGEX: RegExp;
/**
 * Checks if a given value is a valid BCP 47 language tag.
 *
 * Validation is delegated to `Intl.getCanonicalLocales`, which means all
 * formats accepted by the platform are accepted here — including single
 * subtags, case-insensitive region codes, and script subtags. This is
 * intentionally more permissive than a hand-rolled regex so
 * that values coming directly from `navigator.language` (e.g. `"de"` on
 * Firefox or `"de-de"` on Safari) are treated as valid.
 *
 * @param value - The value to check.
 * @returns `true` if `value` is a valid BCP 47 language tag, `false` otherwise.
 *
 * @example
 * // Single primary language subtag (e.g. Firefox)
 * isLocaleFormat('de') // true
 *
 * @example
 * // Standard language-REGION tag
 * isLocaleFormat('en-US') // true
 *
 * @example
 * // Case-insensitive region (e.g. Safari)
 * isLocaleFormat('de-de') // true
 *
 * @example
 * // Script subtag
 * isLocaleFormat('zh-Hant-TW') // true
 *
 * @example
 * // Invalid tag
 * isLocaleFormat('not valid') // false
 * isLocaleFormat('') // false
 * isLocaleFormat(null) // false
 */
export declare function isLocaleFormat(value: any): value is Locale;
export declare function localizeNumber(value: number | string, locale: Locale, options: Intl.NumberFormatOptions): string;
export declare function localizeDate(date: Date, locale: Locale, options: DateFormatOptions): string;
export declare function isDate(value: any): boolean;
export declare function toDate(value: any): Date;
export declare function isoStringToDate(match: RegExpMatchArray): Date;