How to combine splitted buffer

[techducks]

Hello Community,

i have the following arduino code:

void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.write("index:write;name:Lichtsensor-Balkon;lux:777");
  delay(1000);
}

i have the following nodejs code:

const { SerialPort } = require('serialport')

const port = new SerialPort({
    path: '/dev/ttyUSB0',
    baudRate: 9600,
})

port.on("open", function() {
    console.log("-- Connection opened --");

    port.on("data", function(data) {
        console.log(".")
        console.log(data.toString('utf8'));
    });
});

that is my console output:

index:write;name:Lichtsensor-Bal
.
kon;lux:777
.
index:write;name:Lichtsensor-Bal
.
kon;lux:777
.
index:write;name:Lichtsensor-Bal
.
kon;lux:777

I cannot understand why there is a line break resp. why the function is executed twice.I tried to solve the problem with parsers, but without success. I am not sure if i only need to manipulate the node code or also the arduino code. I'm afraid I'm just missing something

[techducks]

I found my solution. You need to add an delimiter to the arduino code:

void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.write("index:write;name:Lichtsensor-Balkon;lux:777\n");
  delay(1000);
}

And then use the delimiter parser:

const { SerialPort } = require('serialport')
const { DelimiterParser } = require('@serialport/parser-delimiter')

const port = new SerialPort({
    path: '/dev/ttyUSB0',
    baudRate: 115200,
})

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

port.on("open", function() {
    console.log("-- Connection opened --");

    parser.on("data", function(data) {
        console.log(".")
        console.log(data.toString(('utf-8')))
    });
});

Now there is only one string / buffer per row / function call:

.
index:write;name:Lichtsensor-Balkon;lux:777
.
index:write;name:Lichtsensor-Balkon;lux:777
.
index:write;name:Lichtsensor-Balkon;lux:777