handleDoOnce.js

handleDoOnce.js

// 可能可以改寫成這樣：
LocationsFetcher.fetchLastResult = null;
LocationsFetcher.fetch = () =>
  if (LocationsFetcher.fetchLastResult) {
    return Promise.reject(new AlreadyCalledError());
  } else {
    return LocationsFetcher.fetchLastResult = doFetchInternal();
  }
};

// Then in your store
handleLocationsFailed(error) {
  if (error instanceof AlreadyCalledError) {
    return; // Do nothing, or ...?
  }
  this.fetchError = error.message;
}