import { Field } from "../field";
/** Validate.isLocale options. */
export interface IIsLocale {
    /** Language/country code separator, defaults to '_'. */
    separator?: string;
}
/** Validate that value is a valid locale (language_COUNTRY). */
export declare function isLocale(value?: string, options?: IIsLocale): string;
export declare class LocaleField extends Field<string> {
    protected readonly options: IIsLocale;
    constructor(options?: IIsLocale);
    validate(value: string): string;
}