Github Fetch error example

fetch-example.js

// Changed after code review
// http://codereview.stackexchange.com/questions/133911
function checkStatus(response) {
  if (response.status >= 200 && response.status < 300) {
    return Promise.resolve(response);
  }

  return response.json()
    .catch(() => {
      const error = new Error(response.statusText);
      return Promise.reject(Object.assign(error, response));
    })
    .then((json) => {
      const error = new Error(json.message || response.statusText);
      return Promise.reject(Object.assign(error, response));
    });
}