improve use of worker variables

src/index.js

@@ -14,26 +14,31 @@ function routeByHosts(host) {
   if (host in routes) {
     return routes[host];
   }
-  return TARGET_UPSTREAM ? TARGET_UPSTREAM : "";
+  if (MODE == "debug") {
+    return TARGET_UPSTREAM;
+  }
+  return "";
 }
 
 async function handleRequest(request) {
   const url = new URL(request.url);
   if (url.pathname == "/v2/") {
-    const resp = new Response({}, { status: 401 });
-    resp.headers = new Headers();
-    if (DEBUG) {
-      resp.headers.set(
+    const headers = new Headers();
+    if (MODE == "debug") {
+      headers.set(
         "Www-Authenticate",
         `Bearer realm="${LOCAL_ADDRESS}/v2/auth",service="cloudflare-docker-proxy"`
       );
     } else {
-      resp.headers.set(
+      headers.set(
         "Www-Authenticate",
         `Bearer realm="https://${url.hostname}/v2/auth",service="cloudflare-docker-proxy"`
       );
     }
-    return resp;
+    return new Response(JSON.stringify({ message: "UNAUTHORIZED" }), {
+      status: 401,
+      headers: headers,
+    });
   }
   const upstream = routeByHosts(url.hostname);
   if (upstream === "") {