import { MessageFunctionType, Result } from '../types';
export interface IsJWTErrors {
    TARGET_ARGUMENT_NOT_A_STRING: MessageFunctionType;
}
export declare const IS_JWT_ERRORS: IsJWTErrors;
/**
 * Tests whether the `target` string is a valid JWT
 *
 * ### Example
 * ```
 * expect(isJWT('eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJsb2dnZWRJbkFzIjoiYWRtaW4iLCJpYXQiOjE0MjI3Nzk2Mzh9.gzSraSYS8EXBxLN_oWnFSRgCzcmJmMjLiuyu5CSpyHI').value).toBeTruthy()
 * ```
 * @param target The target string
 */
export declare function isJWT(target: string): Result<boolean | undefined>;