import { NostrEvent } from "./event.js";
export declare const SeenRelaysSymbol: unique symbol;
/** Normalizes a relay URL by using {@link normalizeURL} and {@link ensureWebSocketURL} */
export declare function normalizeRelayUrl(input: string): string;
/** Marks an event as being seen on a relay */
export declare function addSeenRelay(event: NostrEvent, relay: string): Set<string>;
/** Returns the set of relays this event was seen on */
export declare function getSeenRelays(event: NostrEvent): Set<string> | undefined;
/** Checks if an event was received from a specific relay */
export declare function isFromRelay(event: NostrEvent, relay: string): boolean;
/** A fast check to make sure relay hints are safe to connect to */
export declare function isSafeRelayURL(relay: string): boolean;
/** Merge multiple sets of relays and remove duplicates (ignores invalid URLs) */
export declare function mergeRelaySets(...sources: (Iterable<string> | string | undefined | null)[]): string[];
/** Alias for {@link mergeRelaySets} */
export declare const relaySet: typeof mergeRelaySets;