diff --git a/vite.config.ts b/vite.config.ts
index cfc80279..a0bb9de5 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -97,6 +97,9 @@ export default ({
         cert: fs.readFileSync("./backend/dev_tls_m.localhost.crt"),
       },
     },
+    worker: {
+      format: "es",
+    },
     build: {
       minify: mode === "production" ? true : false,
       sourcemap: true,