/**
 * Generic Middleware function that
 * will run object through all provided functions
 *
 *
 * Minimal example:
 * const MyMiddleware = ({ operation }, next) => {
 *   operation.variables.user = 'admin'
 *   next()
 * }
 *
 * All parameters provided are written in run function JSDoc
 */
export default class Middleware {
    constructor(fns: any);
    /**
     * Run middleware
     * @param {opts.client} GraphQLClient instance
     * @param {opts.operation} Operation object with properties such as query and variables
     * @param {opts.resolve} Used to early resolve the request
     * @param {opts.addResponseHook} Hook that accepts a function that will be run after response is fetched
     * @param {opts.reject} User to early reject the request
     * @param {function} next
     */
    run(opts: any, next: Function): void;
}