/**
 * Etherscan V2 uses a single base URL and selects the network with a `chainid`
 * query parameter. This module maps friendly chain names to their numeric chain
 * id. Anything not covered by the curated map can still be reached by passing a
 * raw numeric chainid.
 *
 * @see https://docs.etherscan.io/etherscan-v2 (V1 was deprecated 2025-08-15)
 */
/** Curated set of commonly requested chains → chainid. */
export declare const CHAINS: Record<string, number>;
/** Retired networks — recognised only so we can fail with a helpful message. */
export declare const RETIRED_CHAINS: Record<string, string>;
/**
 * Resolve a chain name or numeric chainid to a numeric chainid.
 *
 * - `null` / `undefined` / `''` defaults to Ethereum mainnet (1).
 * - A number, or an all-digit string, is passed through once validated as a
 *   positive integer.
 * - A known name is mapped to its chainid.
 * - A retired or unknown name throws — silently switching networks on a
 *   blockchain client is dangerous (wrong-chain reads look successful).
 *
 * @throws {Error} If the chain is invalid, retired or unknown.
 */
export declare function resolveChainId(chain?: string | number | null): number;