/**
 * Normalizes and validates a search input string.
 * Trims whitespace, converts to lowercase, and enforces a maximum length.
 * @param input - The raw input to be sanitized.
 * @param maxLength - The maximum allowed character count (default: 100).
 * @returns The sanitized string, or null if the input is invalid or empty.
 */
export declare const sanitizeSearchString: (input: unknown, maxLength?: number) => string | null;
/**
 * Validates if a value is a valid unique identifier.
 * Ensures the value is a positive, safe integer.
 * @param id - The value to check.
 * @returns True if the value is a number, an integer, and greater than zero.
 */
export declare const isValidId: (id: unknown) => id is number;
/**
 * Safely compares a data string against a search criterion.
 * Returns true if the criterion is empty (AND logic),
 * or if the data string includes the sanitized criterion.
 */
export declare const matches: (dataVal: number | string | null, criteriaVal?: number | string | null) => boolean;
/**
 * Helper to normalize any input (Date or string) into a standard YYYY-MM-DD string.
 * @param date - date to normalize.
 * @returns normalized string date in format 'YYYY-MM-DD'.
 */
export declare const toDateKey: (date: Date | string) => string;
/**
 * Normalizes an input to a sortable numeric timestamp.
 * @param date - date to normalize.
 * @returns stored time value in milliseconds
 */
export declare const toTimestamp: (date: Date | string) => number;