promise idea

a.js

export const fetchCache = (key) => 
  new Promise(resolve => {
    resolve(getCache(key)); // will return undefined is not available.
  });

// in the action then you can do this
fetchCache(CLIENT_API.calculatedJson)
  .then(data => {
    if (data) {
      return data;
    }
    return httpGet(CLIENT_API.calculatedJson);
  })
  .then(data => {
    setCache(data.data);
    dispatch(setCalculatedJson(data))
  })
  .catch(e => {
    dispatch({
      type: FETCH_CALCULATED_JSON_ERROR,
      payload: { error: e.response.data || e },
    });
    console.error(e);
  });