/**
 * Validation utilities for common data types
 *
 * Why: Provides reusable validation functions for email, URI, and other formats
 * Centralizes validation logic and ensures consistency across the application
 */
/**
 * Validates that a property name is safe to use as dynamic object key.
 * Prevents prototype pollution attacks.
 */
export declare function isSafePropertyName(name: string): boolean;
/**
 * Check whether object has an own property key (prototype-safe).
 */
export declare function hasOwnKey(obj: Record<string, unknown>, key: string): boolean;
/**
 * Escape special regex characters in a string.
 * Prevents ReDoS attacks when using dynamic strings in RegExp.
 */
export declare function escapeRegExp(str: string): string;
/**
 * Redact specific header from headers object (case-insensitive)
 */
export declare function redactHeader(headers: unknown, headerName: string): Record<string, unknown>;
/**
 * Redact query parameter from URL string
 */
export declare function redactQueryParam(url: string | undefined, paramName: string): string;
/**
 * Redact parameter from params object
 */
export declare function redactParam(params: unknown, paramName: string): Record<string, unknown>;
/**
 * Validates if a string is a valid email address
 */
export declare function isEmail(value: string): boolean;
/**
 * Validates if a string is a valid URI
 */
export declare function isUri(value: string): boolean;
/**
 * Escape HTML special characters to prevent XSS attacks
 *
 * Why: User-provided strings in error messages must be sanitized
 * before being returned in JSON responses that might be rendered as HTML.
 *
 * Uses escape-html library for reliable HTML entity escaping.
 *
 * @param str - String to escape (can be undefined or null)
 * @returns Escaped string safe for HTML rendering, empty string if input is falsy
 */
export declare function escapeHtmlSafe(str: string | undefined | null): string;
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