NodeJS: serialport parser.on() not working, can't read buffer

All of the answers I found are for the old API, and I can't get the current documentation working.

I am trying to read serial data from a Raspberry Pi GPIO. Here is the code:

const SerialPort = require('serialport');
const Readline = require('@serialport/parser-readline')

const port = new SerialPort('/dev/serial0', {
  baudRate: 9600
})

port.open(() => {
  console.log("port open"); 
})

port.on('data', function (data) {
  console.log('Data:', data)               // <----- This code works
})

const parser = port.pipe(new Readline({ delimiter: '\r\n' }))

parser.on('data', (data) => {
  console.log(data)
})

The port.on() works when I get serial data. However, the parser.on() does not i.e. reading the buffer.

What am I doing wrong?