import { HandlerOptions as RawHandlerOptions, OperationContext } from '../handler';
/**
 * @category Server/fetch
 */
export interface RequestContext {
    Response: typeof Response;
    ReadableStream: typeof ReadableStream;
    TextEncoder: typeof TextEncoder;
}
/**
 * @category Server/fetch
 */
export type HandlerOptions<Context extends OperationContext = undefined> = RawHandlerOptions<Request, RequestContext, Context>;
/**
 * The ready-to-use fetch handler. To be used with your favourite fetch
 * framework, in a lambda function, or have deploy to the edge.
 *
 * Errors thrown from the provided options or callbacks (or even due to
 * library misuse or potential bugs) will reject the handler or bubble to the
 * returned iterator. They are considered internal errors and you should take care
 * of them accordingly.
 *
 * For production environments, its recommended not to transmit the exact internal
 * error details to the client, but instead report to an error logging tool or simply
 * the console.
 *
 * ```ts
 * import { createHandler } from 'graphql-sse/lib/use/fetch';
 * import { schema } from './my-graphql';
 *
 * const handler = createHandler({ schema });
 *
 * export async function fetch(req: Request): Promise<Response> {
 *   try {
 *     return await handler(req);
 *   } catch (err) {
 *     console.error(err);
 *     return new Response(null, { status: 500 });
 *   }
 * }
 * ```
 *
 * @category Server/fetch
 */
export declare function createHandler<Context extends OperationContext = undefined>(options: HandlerOptions<Context>, reqCtx?: Partial<RequestContext>): (req: Request) => Promise<Response>;