import type { SafeEventEmitterProvider } from "eth-json-rpc-middleware/dist/utils/cache.js";
import type { JsonRpcError } from "json-rpc-engine";
export declare function isSafeEventEmitterProvider(x: unknown): x is SafeEventEmitterProvider;
export declare class RpcError extends Error implements JsonRpcError {
    readonly code: number;
    constructor(message: string, code: number);
}
export declare function extractError(error: unknown): Error;