Axios interceptors and asynchronous login

Just use another promise :D

axios.interceptors.response.use(undefined, function (err) {
    return new Promise(function (resolve, reject) {
        if (err.status === 401 && err.config && !err.config.__isRetryRequest) {
            serviceRefreshLogin(
                getRefreshToken(),
                success => { 
                        setTokens(success.access_token, success.refresh_token) 
                        err.config.__isRetryRequest = true
                        err.config.headers.Authorization = 'Bearer ' + getAccessToken();
                        axios(err.config).then(resolve, reject);
                },
                error => { 
                    console.log('Refresh login error: ', error);
                    reject(error); 
                }
            );
        }
        throw err;
    });
});

If your enviroment doesn't suport promises use polyfill, for example https://github.com/stefanpenner/es6-promise

But, it may be better to rewrite getRefreshToken to return promise and then make code simpler

axios.interceptors.response.use(undefined, function (err) {

        if (err.status === 401 && err.config && !err.config.__isRetryRequest) {
            return getRefreshToken()
            .then(function (success) {
                setTokens(success.access_token, success.refresh_token) ;                   
                err.config.__isRetryRequest = true;
                err.config.headers.Authorization = 'Bearer ' + getAccessToken();
                return axios(err.config);
            })
            .catch(function (error) {
                console.log('Refresh login error: ', error);
                throw error;
            });
        }
        throw err;
});

Demo https://plnkr.co/edit/0ZLpc8jgKI18w4c0f905?p=preview

Could do it in the request instead of the response, and it'd probably be cleaner since it'd avoid hitting the server when the access token's expired. Copying from this article:

function issueToken() {
  return new Promise((resolve, reject) => {
    return client({
      ...
    }).then((response) => {
      resolve(response);
    }).catch((err) => {
      reject(err);
    });
  });
}

client.interceptors.request.use((config) => {
  let originalRequest = config;
  if (tokenIsExpired && path_is_not_login) {
    return issueToken().then((token) => {
      originalRequest['Authorization'] = 'Bearer ' + token;
      return Promise.resolve(originalRequest);
    });
  }
  return config;
}, (err) => {
  return Promise.reject(err);
});