serial rpi and node.js

var serialport=require("serialport");
console.log("hi");

var port=new serialport('/dev/ttyACM0',{
baudRate:9600
});
const Readline=serialport.parsers.Readline;
const parser=new Readline();
port.pipe(parser);
port.on('open',onPortOpen);
parser.on('data',onData);
port.on('close',onClose);
port.on('error',onError);
port.write('Hi');

function onPortOpen(){
    console.log("port open ");    
    }      

function onData(data){
    console.log("data received"+data);
    }
        
function onClose(){
console.log("port closed");
}

function onError(){
console.log("Something went wrong in serial communication");
}