fix if statement bug in server

[tavvy]

This change fixes a bug with the handling of HEAD requests.

Previously we would never match on a HEAD request and thus incorrectly create a body to the request, which would throw an uncaught error

[tavvy]

spotted another small bug.
You can test with a curl -I <local-endpoint> and get a thrown error.

Perhaps it would be a good idea in a follow up PR to catch and handle errors thrown by the fetchCallback

        let res;
        try {
          res = (await fetchCallback(new Request(url.toString(), init)));
        } catch {
          res = new Response(null, { status: 50x })
        }

[yusukebe]

Hi @tavvy !

This is a very elementary bug! Thank you for your fix. I'll merge it.

Perhaps it would be a good idea in a follow up PR to catch and handle errors thrown by the fetchCallback

Ah, you are right. It's a good idea.