sense-decorator-cached.js

export const cached = ({ttl = 60000}) => wrappedFunc => {
  // require the action creator to have a KEY
  if (!wrappedFunc.KEY) {
    throw new Error('Must use key() decorator first before fetching');
  }

  // the higher order action creator
  const cachedWrapped = (...args) => (dispatch, getState) => {
    const keyValue = wrappedFunc.KEY.apply(this, args);

    // check if the action is cached
    const cacheItem = getState().cache[keyValue];
    if (cacheItem && cacheItem.expireTime > Date.now()) {
      return;
    }

    // assume the wrapped action creator returns an api promise
    const requestPromise = wrappedFunc(...args)(dispatch, getState).then(response => {
      // set the action as cached
      dispatch(setCache(keyValue));
    });

    return requestPromise;
  };

  // redecorate the new action creator with the original key
  return key(wrappedFunc.KEY)(cachedWrapped);
};