import { RequestMiddleware } from 'graphql-request/build/esm/types';
/**
 * Creates a request middleware that automatically handles file uploads
 * by converting requests to multipart/form-data when files are detected in variables.
 *
 * This middleware intercepts the request before it's sent, checks for File/Blob objects
 * in the variables, and if found, converts the request body to FormData following
 * the GraphQL multipart request specification.
 *
 * @param existingMiddleware - Optional existing middleware to chain with
 * @returns A RequestMiddleware function that handles file uploads
 */
export declare const createFileUploadMiddleware: (existingMiddleware?: RequestMiddleware) => RequestMiddleware;