Dynamic configuration based on request url

[DanielPower]

I need to route the wildcard subdomain https://*.localhost:8080 to https://*.mydomain.com. I recognize that this is achievable by using a function router. However I'm not sure if it's possible to make other config fields dynamic based on the request url. For example, I also need cookieDomainRewrite and headers to change based on the subdomain.

Ideally I'd like to be able to do something like the following example, where the config can be re-computed for each request.

import { getToken } from 'token';
const webpackProxyMiddleware = createProxyMiddleware('/api', (req) => {
  const subdomain = req.hostname.split('.')[0];
  return {
    pathRewrite: {
      '^/api': '',
    },
    router: `${subdomain}.mydomain.com`,
    cookieDomainRewrite: ({
      [proxyUrl.hostname]: `$(subdomain}.localhost:8080`,
      [`.${proxyUrl.hostname}`]: `.${subdomain}.localhost:8080`,
    }),
    headers: {
      token: getToken(subdomain)
    },
  };
});

From reading the documentation, I'm not sure if this is currently achievable with the library. But if you have any ideas, I'd greatly appreciate it.