import { GuardClass, GuardFunctionWithArray, OptionalGuardFunctionWithArray } from '../global';
export declare type BooleanMode = 'normal' | 'loose' | 'strict';
declare class BooleanGuard implements GuardClass<boolean> {
    private mode;
    get required(): GuardFunctionWithArray<boolean>;
    get optional(): OptionalGuardFunctionWithArray<boolean>;
    get loose(): BooleanGuard;
    get strict(): BooleanGuard;
    constructor(mode?: BooleanMode);
}
declare const _default: BooleanGuard;
export default _default;