Bulk origin override

/**
 * An object with different URLs to fetch
 * @param {Object} ORIGINS
 */
const ORIGINS = {
  "starwarsapi.yourdomain.com": "swapi.dev",
  "google.yourdomain.com": "www.google.com",
}

function handleRequest(request) {
  const url = new URL(request.url)
  // Check if incoming hostname is a key in the ORIGINS object
  if (url.hostname in ORIGINS) {
    const target = ORIGINS[url.hostname]
    url.hostname = target
    // If it is, proxy request to that third party origin
    return fetch(url.toString(), request)
  }

  // Otherwise, process request as normal
  return fetch(request)
}

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