export declare function isPotentiallyUnsafeDateString(mixed: any): mixed is string;
export declare function isValidDateString(mixed: any): mixed is string;
export declare function isBeforeString(mixed: any, x: Date): mixed is string;
export declare function isAfterString(mixed: any, x: Date): mixed is string;
export declare function isBeforeOrAtString(mixed: any, x: Date): mixed is string;
export declare function isAfterOrAtString(mixed: any, x: Date): mixed is string;
export declare function isRangeString(mixed: any, args: {
    min?: Date;
    max?: Date;
}): mixed is string;