export declare const isDate: (value: string | null | undefined) => boolean;
export declare const getDayDiff: (fromDate: Date, toDate: Date) => number | null;
export declare function isDefined<T>(input: T | null | undefined): input is T;
export declare function isDefinedAndNotEmpty<T>(input: T | null | undefined): input is T;
/***
 * This function receives an input (string or number) and returns true if it is a number
 * @param input - The input to check if it is a number
 * @returns true if the input is a number
 */
export declare function isANumber(input: unknown): input is number;