actions.js

export const RESULTS_POLLING = 'RESULTS_POLLING';
const setPolling = val => ({ type: RESULTS_POLLING, pollingType: val });

export const SET_POLLING_DURATION = 'SET_POLLING_DURATION';
const setPollingDuration = (val, count, dates) => (
  { type: SET_POLLING_DURATION, duration: val, count, dates }
);

export const INCREMENT_POLL_COUNT = 'INCREMENT_POLL_COUNT';
const incrementPollCount = () => ({ type: INCREMENT_POLL_COUNT });

export const initiatePolling = data => (
  (dispatch, getState) => {
    const state = getState();
    const pollCount = state.results.polling.pollCount;
    if (pollCount === 0) dispatch(setPolling('indeterminate'));
    const { REPORTS_SUMMARY_URL } = config;
    fetch(`${REPORTS_SUMMARY_URL}/${data.temporary_id}`, { credentials: 'include' })
      .then((response) => {
        // if (!response.ok) throw Error(response.statusText);
        const statusPromise = Promise.resolve(response.status);
        return Promise.all([response.json(), statusPromise]);
      })
      .then((promises) => {
        const [d, status] = promises;
        if (status === 200) {
          dispatch(incrementPollCount());
          dispatch(setPolling(null));
          return dispatch(processResults(d));
        }
        if (pollCount === 0) {
          dispatch(setPollingDuration(d.predicted_wait_time, d.time_entry_count, d.dates));
        }
        dispatch(incrementPollCount());
        const timeout = (d.predicted_wait_time * 1000) / 5;
        return setTimeout(() => { dispatch(initiatePolling(d)); }, Math.max(timeout, 1));
      });
  }
);

// ...

export const fetchSummaryRows = () => (
  (dispatch, getState) => {
    const { REPORTS_SUMMARY_URL } = config;

    dispatch({ type: REQUEST_RESULTS });

    const payload = buildPayload(getState());
    payload.today = getCurrentUnixDate();

    return fetch(REPORTS_SUMMARY_URL, {
      credentials: 'include',
      method: 'POST',
      headers: {
        // eslint-disable-next-line
        'Accept': 'application/json',
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(payload)
    })
      .then((response) => {
        // if (!response.ok) throw Error(response.statusText);
        const statusPromise = Promise.resolve(response.status);
        return Promise.all([response.json(), statusPromise]);
      })
      .then((promises) => {
        const [data, status] = promises;
        if (status === 202) {
          return dispatch(initiatePolling(data));
        }
        return dispatch(processResults(data));
      });
      // .catch(() => dispatch(toggleErrorState()));
  });