var serialport = require("serialport");
var _ = require('lodash');

const port = "/dev/tty.usbserial-14420";

let f3 = new serialport(port, {
  baudRate: 9600,
  databits: 8,
  parity: 'none',
  stopBits: 1,
  flowControl: false
})

const Readline = new serialport.parsers.Readline();
f3.pipe(Readline);

f3.on('open', (error) => {
  console.log('port open');
  //init
  if(error) {
console.log(error);
  } else {
    f3.write(hexStringToBinaryBuffer('F2 00 00 03 43 32 32 03 b1'));

  }
});

Readline.on('data', (data) => {
    console.log("data received "+data);
});

f3.on('error', (error) => {
  console.log('error: ' + error);
})

const hexStringToBinaryBuffer = (string) => {
  const subStrings = Array.from(string);
  let previous = null;
  const bytes = [];
  _.each(subStrings, (val) => {
    if (previous === null) { // Converting every 2 chars as binary data
      previous = val;
    } else {
      const value = parseInt(`0x${previous}${val}`, 16);
      bytes.push(value);
      previous = null;
    }
  });

  let returnValue = Buffer.from(bytes);
  console.log(returnValue);
  return returnValue;
};