run sirv in dev-mode in “development” env

app/server.js

@@ -4,13 +4,16 @@ import sapper from 'sapper';
 import compression from 'compression';
 import { manifest } from './manifest/server.js';
 
+const { PORT, NODE_ENV } = process.env;
+const dev = NODE_ENV === 'development';
+
 polka() // You can also use Express
 	.use(
 		compression({ threshold: 0 }),
-		sirv('assets'),
+		sirv('assets', { dev }),
 		sapper({ manifest })
 	)
-	.listen(process.env.PORT)
+	.listen(PORT)
 	.catch(err => {
 		console.log('error', err);
 	})