demo-auth-flow/demo-client-app/runProxy.js

const { createProxyMiddleware } = require("http-proxy-middleware");
const express = require('express');

const PORT = 8080;

console.log(`Starting Proxy on port ${PORT}`);

const app = express();

app.use(createProxyMiddleware({ target: "http://localhost:8081", changeOrigin: true, ws: true }));
app.listen(PORT, () => {
    console.log(`Started on http://localhost:${PORT}`);
});