Arduino Firmata I2C Slave writer nodejs

Question

Hi I'm trying to read code from an slave arduino using nodejs connected with and arduino through firmata, however i can't get the correct values in the read.

I'm using this package https://www.npmjs.com/package/firmata

Also I tried sending data from the Master to slave and it works correctly.

The slave arduino code:

#include <Wire.h> 

void setup() {
  Wire.begin(8);
  Wire.onRequest(requestEvent);
}

void loop() {
  delay(500); 
}

void requestEvent() {
  uint8_t buffer[4];
  buffer[0] = 12;
  buffer[1] = 23;
  buffer[2] = 39;
  buffer[3] = 78;
  Wire.write(buffer, 4);
}

The Firmata code:

let firmata = require("firmata");

board = new firmata('COM3', {samplingInterval: 1000});
board.on("ready", function() {
    this.i2cConfig();
    this.i2cRead(8,4, function(data) {
      console.log("received data");
      console.log(data);
    });
});

The response i get is:

received data
[189,255,255,255]