I try to upgrade connection and promise return undefined

[banocean]

I try to upgrade connection and promise return undefined Deno 1.14, Windows 10

import { Application, Router } from "https://deno.land/x/oak/mod.ts";

const router = new Router();

router.get("/gateway", async (ctx) => {

    if(!ctx.isUpgradable) return ctx.response.body = "boomers opening websocket"

    const socket = await ctx.upgrade();

    console.log(socket)

})

const app = new Application();
app.use(router.routes());
app.use(router.allowedMethods());

await app.listen({ port: 8000 });

[banocean]

I forgot reload cache to update module (deno cache --reload=src/index.js)