Proxy Trfyx with Firebase Hosting

firebase init functions
cd functions
npm install express express-http-proxy

const { onRequest } = require("firebase-functions/v2/https");
const express = require("express");
const proxy = require("express-http-proxy");

const app = express();
app.set("trust proxy", true);

app.use(
  "/script.js",
  proxy("https://app.trfyx.com", {
    proxyReqPathResolver: () => "/script.js",
  }),
);

app.use(
  "/api/events",
  proxy("https://app.trfyx.com", {
    proxyReqPathResolver: () => "/api/events",
  }),
);

exports.trfyxProxy = onRequest(app);

{
  "hosting": {
    "rewrites": [
      { "source": "/script.js", "function": "trfyxProxy" },
      { "source": "/api/events", "function": "trfyxProxy" }
    ]
  }
}

<script
  defer
  data-website-id="YOUR_TRFYX_PROJECT_ID"
  data-domain="yourdomain.com"
  src="/script.js"
></script>