/**
 * hppx — Superior HTTP Parameter Pollution protection middleware
 *
 * - Protects against parameter and prototype pollution
 * - Supports nested whitelists via dot-notation and leaf matching
 * - Merge strategies: keepFirst | keepLast | combine
 * - Multiple middleware compatibility: arrays are "put aside" once and selectively restored
 * - Exposes req.queryPolluted / req.bodyPolluted / req.paramsPolluted
 * - TypeScript-first API
 */
declare module "express-serve-static-core" {
    interface Request {
        queryPolluted?: Record<string, unknown>;
        bodyPolluted?: Record<string, unknown>;
        paramsPolluted?: Record<string, unknown>;
    }
}
type RequestSource = "query" | "body" | "params";
type MergeStrategy = "keepFirst" | "keepLast" | "combine";
interface SanitizeOptions {
    whitelist?: string[] | string;
    mergeStrategy?: MergeStrategy;
    maxDepth?: number;
    maxKeys?: number;
    maxArrayLength?: number;
    maxKeyLength?: number;
    trimValues?: boolean;
    preserveNull?: boolean;
}
interface HppxOptions extends SanitizeOptions {
    sources?: RequestSource[];
    /** When to process req.body */
    checkBodyContentType?: "urlencoded" | "any" | "none";
    excludePaths?: string[];
    strict?: boolean;
    onPollutionDetected?: (req: Record<string, unknown>, info: {
        source: RequestSource;
        pollutedKeys: string[];
    }) => void;
    logger?: (err: Error | unknown) => void;
    /** Enable logging when pollution is detected (default: true) */
    logPollution?: boolean;
}
interface SanitizedResult<T> {
    cleaned: T;
    pollutedTree: Record<string, unknown>;
    pollutedKeys: string[];
}
declare const DEFAULT_SOURCES: RequestSource[];
declare const DEFAULT_STRATEGY: MergeStrategy;
declare const DANGEROUS_KEYS: Set<string>;
/**
 * @internal — test-only helper that resets the module-level path segment cache.
 * Public callers must not depend on this; it exists solely so tests can verify
 * cache eviction behavior without exposing the internal Map.
 */
declare function __resetPathSegmentCache(): void;
declare function sanitize<T extends Record<string, unknown>>(input: T, options?: SanitizeOptions): T;
type ExpressLikeNext = (err?: unknown) => void;
declare function hppx(options?: HppxOptions): (req: any, res: any, next: ExpressLikeNext) => any;

export { DANGEROUS_KEYS, DEFAULT_SOURCES, DEFAULT_STRATEGY, type HppxOptions, type MergeStrategy, type RequestSource, type SanitizeOptions, type SanitizedResult, __resetPathSegmentCache, hppx as default, sanitize };