import { SagaIterator } from 'redux-saga';
import type { FetchCtx, FetchJsonCtx, Next } from './types';
/**
 * Automatically sets `content-type` to `application/json` when
 * that header is not already present.
 */
export declare function headersMdw<CurCtx extends FetchCtx = FetchCtx>(ctx: CurCtx, next: Next): SagaIterator<any>;
/**
 * This middleware takes the `ctx.response` and sets `ctx.json` to the body representation
 * requested.  It uses the `ctx.bodyType` property to determine how to represent the body.
 * The default is set to `json` which calls `Response.json()`.
 *
 * @example
 * ```ts
 * const fetchUsers = api.get('/users', function*(ctx, next) {
 *  ctx.bodyType = 'text'; // calls Response.text();
 *  yield next();
 * })
 * ```
 */
export declare function jsonMdw<CurCtx extends FetchJsonCtx = FetchJsonCtx>(ctx: CurCtx, next: Next): SagaIterator<any>;
export declare function apiUrlMdw<CurCtx extends FetchJsonCtx = FetchJsonCtx>(baseUrl?: string): (ctx: CurCtx, next: Next) => SagaIterator<any>;
/**
 * If there's a slug inside the ctx.name (which is the URL segement in this case)
 * and there is *not* a corresponding truthy value in the payload, then that means
 * the user has an empty value (e.g. empty string) which means we want to abort the
 * fetch request.
 *
 * e.g. `ctx.name = "/apps/:id"` with `payload = { id: '' }`
 *
 * Ideally the action wouldn't have been dispatched at all but that is *not* a
 * gaurantee we can make here.
 */
export declare function payloadMdw<CurCtx extends FetchJsonCtx = FetchJsonCtx>(ctx: CurCtx, next: Next): Generator<any, void, unknown>;
export declare function fetchMdw<CurCtx extends FetchCtx = FetchCtx>(ctx: CurCtx, next: Next): SagaIterator<any>;
/**
 * This middleware will retry failed `Fetch` request if `response.ok` is `false`.
 * It accepts a backoff function to determine how long to continue retrying.
 * The default is an exponential backoff {@link backoffExp} where the minimum is
 * 1sec between attempts and it'll reach 4s between attempts at the end with a
 * max of 5 attempts.
 *
 * An example backoff:
 * @example
 * ```ts
 *  // Any value less than 0 will stop the retry middleware.
 *  // Each attempt will wait 1s
 *  const backoff = (attempt: number) => {
 *    if (attempt > 5) return -1;
 *    return 1000;
 *  }
 *
 * const api = createApi();
 * api.use(requestMonitor());
 * api.use(api.routes());
 * api.use(fetcher());
 *
 * const fetchUsers = api.get('/users', [
 *  function*(ctx, next) {
 *    // ...
 *    yield next();
 *  },
 *  // fetchRetry should be after your endpoint function because
 *  // the retry middleware will update `ctx.json` before it reaches your middleware
 *  fetchRetry(backoff),
 * ])
 * ```
 */
export declare function fetchRetry<CurCtx extends FetchJsonCtx = FetchJsonCtx>(backoff?: (attempt: number) => number): (ctx: CurCtx, next: Next) => Generator<any, void, unknown>;
/**
 * This middleware is a composition of other middleware required to use `window.fetch`
 * {@link https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API} with {@link createApi}
 */
export declare function fetcher<CurCtx extends FetchJsonCtx = FetchJsonCtx>({ baseUrl, }?: {
    baseUrl?: string;
}): (context: CurCtx, next?: import("./types").Middleware<import("./types").PipeCtx<any>> | undefined) => SagaIterator<void>;