asyncActionCreator.js

import { startFetch, abortFetch, errorFetch, updateFetch } from './syncActionCreators';

// Run the async fetch if the data is stale, otherwise abort the fetch and log it
export const updateDemoContentAsync = () => {
  // Redux Thunk allows this, see its docs for more detail
  return (dispatch, getState) => {
    
    // Get the state of the store synchronously for the REDUCER IN QUESTION, e.g. myContent here
    const timeSinceLastFetch = getState().myContent.lastFetched;
    
    // perform the async call if the data is older than the allowed limit
    const isDataStale = Date.now() - timeSinceLastFetch > timeToStale;
    if (isDataStale) {
      dispatch(startFetch());

      // Run the async fetch
      myApi.fetchData()
        .then(content => {
          dispatch(updateFetch(content));
        })
        .catch(err => {
          dispatch(errorFetch(err));
        });
    } else {
      dispatch(abortFetch());
    }
  };
};