Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object

My app has a simple routing with ssr. I followed your git code to add server and below is my code.

index.tsx

import React from "react";
import ReactDOM from "react-dom";
import "./index.css";
import App from "./App";
import * as serviceWorker from "./serviceWorker";
import "bootstrap/dist/css/bootstrap.min.css";

ReactDOM.hydrate(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById("root")
);
serviceWorker.unregister();

App.tsx

import React from "react";
import {
  BrowserRouter as Router,
  Switch,
  Route,
  Redirect,
} from "react-router-dom";
import Home from "./components/home/Home";
import Tournament from "./components/tournament/Tournament";
import "./App.css";

function App() {
  return (
    <div className="App">
      <Router>
        <Switch>
          <Route path="/" exact strict component={Home} />
          <Route
            path="/tournament/:tourId/:tourName"
            exact
            component={Tournament}
          />
          <Redirect from="*" to={"/"} />
        </Switch>
      </Router>
    </div>
  );
}
export default App;

server/server.js

import path from "path";
import fs from "fs";

import express from "express";
import React from "react";
import ReactDOMServer from "react-dom/server";

import App from "../src/App";

const PORT = 8000;
const app = express();

const router = express.Router();

app.get("/*", (req, res) => {
  const context = {};
  const app = ReactDOMServer.renderToString(
    <App />
  );

  const indexFile = path.resolve("./build/index.html");
  fs.readFile(indexFile, "utf8", (err, data) => {
    if (err) {
      console.error("Something went wrong:", err);
      return res.status(500).send("Oops, better luck next time!");
    }

    return res.send(
      data.replace('<div id="root"></div>', `<div id="root">${app}</div>`)
    );
  });
});

router.use(
  express.static(path.resolve(__dirname, "..", "build"), { maxAge: "30d" })
);

// tell the app to use the above rules
app.use(router);

app.use(express.static("./build"));
app.listen(PORT, () => {
  console.log(`SSR running on port ${PORT}`);
});

server/index.js

require("ignore-styles");

require("@babel/register")({
  ignore: [/(node_modules)/],
  presets: ["@babel/preset-env", "@babel/preset-react"],
});

require("./server");

When I run node server/index.js it starts the server which is fine. But when I lauch the http://localhost:8000/ on browser, it gives me the below error

Warning: React.createElement: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: object. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.

Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports. at ReactDOMServerRenderer.render ...

satansdeer / ssr-example