@aspectus/superagent-fetch/src/main.js

Custom fetcher that adapts [superagent](https://github.com/visionmedia/superagent) library to the default Fetch API.

import { partial, compose } from 'ramda';
import superagent from 'superagent';
import cancellablePromiseProxy from '@aspectus/cancellable-promise-proxy';
import progressPromiseProxy from '@aspectus/progress-promise-proxy';

const FOLLOW_REDIRECT = 'follow';
const nullHandler = () => null;

export function createRequestFromFetch(agent, url, init = {}) {
  const {
    method = 'GET',
    headers = {},
    redirect = FOLLOW_REDIRECT,
    body,
  } = init;

  return agent(method, url)
    .set(headers)
    .redirects(redirect === FOLLOW_REDIRECT ? 5 : 0)
    .send(body);
}

export function makeRequest(agent, proxy, resource, init = {}) {
  const request = createRequestFromFetch(agent, resource, init);
  // HACK: Forcing progress handling in superagent.
  // With empty progress handlers list it would not subscribe on actual
  // progress event at all.
  request.on('progress', nullHandler);

  return proxy(
    new Promise((resolve, reject) => request.then(resolve, reject)),
    {
      request,
      cancelController: request,
      progressEmitter: request,
    }
  );
}

export const baseProxy = compose(cancellablePromiseProxy, progressPromiseProxy);

export default partial(makeRequest, [superagent, baseProxy]);