Send bytes from arduino and convert to numbers

[dj-fiorex]

Hello to all,
Thanks for the effort developing this library! i'm trying something simple to be able to try serialport and decide to rewrite an existing program to use node (which i'm more familiar with). So i tried to write the most simple possible scenario: one arduino sending 25 bytes to node serialport, 24 bytes is 3 double (8 bytes for every double) and the twenty-fifth byte is a terminator to be able to use the "DelimiterParser". This is the code:
Arduino program

#include <Arduino.h>

double values[4] = {1.0, 2.0, 3.0};
void setup()
{
  // initialize serial:
  Serial.begin(9600);
  Serial.println(sizeof(double)); //print 8
  Serial.println(sizeof(float));  // print 4
}

void loop()
{
  byte *p = (byte *)values;
  for (int i = 0; i < 24; i++)
  {
    Serial.write(p[i]);
  }
  Serial.write(0x3A);
  delay(5000);
}

Node serialport program:

import { SerialPort } from "serialport";
import { DelimiterParser } from "@serialport/parser-delimiter";
// Create a port
const port = new SerialPort({
  path: "COM7",
  baudRate: 9600,
});

const parser = port.pipe(new DelimiterParser({ delimiter: [0x3a] }));
parser.on("data", (d) => {
  const double = d.readDoubleLE(0);
  const double1 = d.readDoubleLE(1);
  const double2 = d.readDoubleLE(2);

  console.log({
    double,
    double1,
    double2,
  });
});

So the problem is that node program prints:

{
  double: 1,
  double1: 1.7765824089018436e-307,
  double2: 3.47328271065196e-310,
}

but it should be printing 1, 2, 3
am i missing something? what's wrong with my code?

Thanks a lot!

[dj-fiorex]

I will answer to my self! I didn't read the docs well (https://nodejs.org/api/buffer.html#bufreaddoublebeoffset)!
i need to pass the number of bytes to skip to readDoubleLE, so the code must be:

...
parser.on("data", (d) => {
  const double = d.readDoubleLE(0);
  const double1 = d.readDoubleLE(8);
  const double2 = d.readDoubleLE(16);

  console.log({
    double,
    double1,
    double2,
  });
});
...
now it works as expected!