import { GuardResult } from './types';
export declare function guardIsString(input: unknown): GuardResult;
export declare function guardNotEmpty(input: string): GuardResult;
export declare function guardValidCharacters(input: string, allowedChars: RegExp): GuardResult;
export declare function guardLength(input: string, expectedLength: number, errorMessage: string): GuardResult;
export declare function chainGuards(...guards: GuardResult[]): GuardResult;