let fetching = {};

export default (url, options = {}) => {
  if (fetching[url]) {
    return Promise.reject(`Fetch responsibly, a fetch for the same url (${url}) is already in progress (options are ignored).`);
  }

  fetching[url] = true;

  return fetch(url, options).then(response => {
    fetching[url] = false;
    return response;
  });
};