// The collection of URLs in all regions.
const urls = {
  CN: 'https://www.example.com/zh-CN',
  US: 'https://www.example.com/en-US',
};

// The default redirect URL.
const defaultUrl = 'https://www.example.com/en-US';

/**
 * Redirect to the target URL based on the region of the current request.
 * @param { Request } request
 */
function handleRequest(request) {
  // Obtain the region of the current request.
  const alpha2code = request.eo.geo.countryCodeAlpha2;
  // The target URL that you want to use for redirection.
  const url = urls[alpha2code] || defaultUrl;

  return Response.redirect(url, 302);
}

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request));
});