self/app/server/server.ts

import express, {Request, Response} from 'express';
import bodyParser from 'body-parser';
import fs from 'fs';

const app = express();

// parse application/json
app.use(bodyParser.json());

app.post('/data', (req: Request, res: Response) => {
  const data = req.body;
  //   console.log('data:', data);
  console.log('typeof data:', typeof data);
  fs.writeFile('data2.json', JSON.stringify(data, null, 2), err => {
    if (err) {
      console.log(err);
      res.status(500).send('An error occurred while writing file');
    } else {
      res.send('File written successfully');
    }
  });
});

const port = 3000;
app.listen(port, () => {
  console.log(`Server running on http://localhost:${port}`);
});