import { Filter as CoreFilter } from "nostr-tools";
import { NostrEvent } from "./event.js";
export declare const INDEXABLE_TAGS: Set<string>;
export declare const EventIndexableTagsSymbol: unique symbol;
/** Returns a Set of tag names and values that are indexable */
export declare function getIndexableTags(event: NostrEvent): Set<string>;
/**
 * Extended Filter type that supports NIP-91 AND operator and NIP-50 search filter field
 */
export type Filter = CoreFilter & {
    /** NIP-91 AND operator support */
    [key: `&${string}`]: string[] | undefined;
    /** NIP-50 search filter field */
    search?: string;
};
/**
 * Copied from nostr-tools and modified to use {@link getIndexableTags}
 * Extended to support NIP-91 AND operator with `&` prefix
 * @see https://github.com/nbd-wtf/nostr-tools/blob/a61cde77eacc9518001f11d7f67f1a50ae05fd80/filter.ts
 */
export declare function matchFilter(filter: Filter, event: NostrEvent): boolean;
/** Copied from nostr-tools and modified to use {@link matchFilter} */
export declare function matchFilters(filters: Filter[], event: NostrEvent): boolean;
/** Copied from nostr-tools and modified to support undefined values and NIP-91 AND operator */
export declare function mergeFilters(...filters: Filter[]): Filter;
/** Check if two filters are equal */
export declare function isFilterEqual(a: Filter | Filter[], b: Filter | Filter[]): boolean;