How to reinitialize in node-serialport after an error accessing the COM port?

Question

Node.js

The application works as a web server. When accessing the web server address, a command is sent to the com port and the data in the response is transmitted to the client. But when the connection with the equipment is interrupted / the equipment is turned off, the application, after a certain timeout, writes an error. But when you re-access, after the connection is restored, the equipment also continues to write a communication error. How to do a reinitialization so that it re-applies to the com port?

The program itself

const express = require('express');
const app = express();
const SerialPort = require('serialport');

app.get('/', (req, res) => {
    let comPort = req.query.comPort
    const port = new SerialPort('COM' + comPort, {
        baudRate: 2400,
        dataBits: 7,
        parity: 'even'
    });
    const Readline = SerialPort.parsers.Readline;
    const parser = new Readline();
    port.pipe(parser);

    port.on('open', () => {
        port.write("Q\r\n", (err) => {
            if (err) {
                return console.log('Error on write: ', err.message);
            }
        })

        parser.on('data', (data) => {
            console.log('data: ' + data)
            port.close()
        })
    });

// open errors will be emitted as an error event
    port.on('error', (err) => {
        console.log('Error: ', err.message);
        res.status(500).send('Error: ' + err.message)
    });

    port.on('close', () => {
        console.log('closed');
        res.json(user_data)
    });
});
app.listen(3000, () => {
    console.log('Example app listening on port 3000!');
});