Running many WebSocket servers

import http from 'http';import WebSocket, { WebSocketServer as WSWebSocketServer } from 'ws';// work with commonjs and esmconst WebSocketServer = WebSocket.Server || WSWebSocketServer;export const createWebsocketMiddleware = (  propertyName = 'ws',  options = {},) => {  if (options instanceof http.Server) options = { server: options };  const wsServers = {};  const getOrCreateWebsocketServer = (url: string) => {    const server = wsServers[url];    if (server) {      return server;    }    const newServer = new WebSocketServer({      ...(options.wsOptions || {}),      noServer: true,    });    wsServers[url] = newServer;    return newServer;  };  const websocketMiddleware = async (ctx, next) => {    const upgradeHeader = (ctx.request.headers.upgrade || '')      .split(',')      .map((s) => s.trim());    if (~upgradeHeader.indexOf('websocket')) {      const wss = getOrCreateWebsocketServer(ctx.url);      ctx[propertyName] = () =>        new Promise((resolve) => {          wss.handleUpgrade(            ctx.req,            ctx.request.socket,            Buffer.alloc(0),            (ws) => {              wss.emit('connection', ws, ctx.req);              resolve(ws);            },          );          ctx.respond = false;        });      ctx.wss = wss;    }    await next();  };  return websocketMiddleware;};

const app = new Koa();app.use(createWebsocketMiddleware());const routes = new Router();routes.all('/ws', async (ctx) => {   if (ctx.wss) { // check if this is a websocket connection      // connect to websocket - upgrade      const client = await ctx.ws();    }});