thunk poller - easily poll redux thunk functions

redux-thunk-poll.js

// createPollingAction() returns a thunk which continually polls, once invoked.
// subsequent invocations will cancel the previous poll queue.

const createPoller = (interval, initialDelay) => {
  let timeoutId = null;
  let poller = () => {};
  return fn => {
    window.clearTimeout(timeoutId);
    poller = () => {
      timeoutId = window.setTimeout(poller, interval);
      return fn();
    };
    if (initialDelay) {
      return timeoutId = window.setTimeout(poller, interval);
    }
    return poller();
  };
};

export const createPollingAction = (action, interval, initialDelay) => {
  const poll = createPoller(action, initialDelay);
  return () => (dispatch, getState) => poll(() => action(dispatch, getState));
};

// -----------------------

// example usage - when the returned thunk is invoked, it calls the thunk every 30 seconds
const fetchAction = createPollingAction(dispatch => {
  fetch('foo').then(
      json => dispatch(success(json)), 
      e => dispatch(failure(e))
  );
}, 30000);