NodeJS server with PostgreSQL streaming

app.js

const http = require('http');
const Pool = require('pg-pool');
const bluebird = require('bluebird');
const JSONStream = require('JSONStream');
const QueryStream = require('pg-query-stream');

const pool = new Pool({
  user: 'postgres',
  host: 'localhost',
  database: 'data',
  password: 'postgres',
  poolSize: 20,
  Promise: bluebird
});

const server = http.createServer(async (req, res) => {
  try {
    const client = await pool.connect();
    const query = new QueryStream('SELECT * FROM generate_series(0, $1) num', [10000]);
    const stream = client.query(query);

    // release the client when the stream is finished
    stream.on('end', () => client.release());
    stream.pipe(JSONStream.stringify()).pipe(res);
  } catch (error) {
    console.error(error);
  }
});

const hostname = '127.0.0.1';
const port = 3000;
server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});