Slight cleanup

src/Server.js

@@ -45,17 +45,16 @@ function middleware(bundler) {
     function respond() {
       if (bundler.errored) {
         return send500();
-      } else if (!req.url.startsWith(bundler.options.publicURL)) {
-        // If the URL doesn't start with the public path, send the main HTML bundle
+      } else if (
+        !req.url.startsWith(bundler.options.publicURL) ||
+        path.extname(req.url) === ''
+      ) {
+        // If the URL doesn't start with the public path, or the URL doesn't
+        // have a file extension, send the main HTML bundle.
         return sendIndex();
       } else {
         // Otherwise, serve the file from the dist folder
         req.url = req.url.slice(bundler.options.publicURL.length);
-        // If we're serving an html bundle, and the requested path has not file
-        // extension, serve the index.html. Otherwise go to the file server.
-        if (bundler.mainAsset.type === 'html' && path.extname(req.url) == "") {
-          return sendIndex();
-        }
         return serve(req, res, send404);
       }
     }