function mfetch (url, options = {}) {
  const INTERVAL_TIME = 500;
  const TIMEOUT = 20000;
  function waitForRenewComplete (){
    return new Promise((resolve, reject) => {
      const timeout_time = Date.now() + TIMEOUT;
      const t = setInterval(()=> {
        if(!localStorage.getItem('renewing')){
          clearInterval(t);
          resolve();
        } else if(Date.now() > timeout_time){
          localStorage.removeItem('renewing');
          reject({error: 'token renovation wait timed out'});
        }
      }, INTERVAL_TIME)
    });
  }
  const RENOVATION_ERRORS = [
    'JWT_EXPIRED',
    'JWT_INVALID_SIGNATURE',
  ];
  return window.fetch(url, Object.assign({}, options, {credentials: 'include'}))
    .then(res => {
      const mapp_auth_error = res.headers.get('MAPP-auth-error-message');
      if (mapp_auth_error && res.status !== 403) {
        if (RENOVATION_ERRORS.some(error => error === mapp_auth_error)){
          if(!localStorage.getItem('renewing')){
            //if(localStorage.getItem('token') !== access_token){
            //return mfetch(url, options);
            //}
            localStorage.setItem('renewing', true);
            const renew_url = `${"https://crm.walcu.com/"}refresh_token/renew`;
            return window.fetch(renew_url).then(renew_response => {
              const renew_mapp_auth_error = renew_response.headers.get('MAPP-auth-error-message');
              if(renew_mapp_auth_error){
                return Promise.reject(renew_mapp_auth_error);
              } else {
                return renew_response.json();
              }
            }).then((decoded_token) => {
              if(decoded_token){
                localStorage.setItem('decoded_token', JSON.stringify(decoded_token));
                localStorage.removeItem('renewing');
                return mfetch(url, options);
              } else {
                return Promise.reject('UNEXPECTED_AUTH_ERROR');
              }
            })
          } else {
            return waitForRenewComplete().then(() => mfetch(url,options));
          }
        } else {
          localStorage.removeItem('renewing');
          return Promise.reject(mapp_auth_error);
        }
      } else {
        return res;
      }
    })
    .catch(error => {
      localStorage.removeItem('renewing');
      if(error instanceof Error){
        return Promise.reject(error);
      } else {
        localStorage.setItem('last_path', window.location.pathname);
        if(!options.ignore_redirect_on_failure) window.location = '/'
      }
    });
}