Using BLE technology when working with beacon in React Native

import { BleManager } from "react-native-ble-plx";

const NAME = "HOLY-IOT";

const bleManager = new BleManager();

// Function to start scanning BLE devices
function startScanning() {
  // The first parameter is the UUIDs of services (null if you want to scan all devices)
  // Second parameter - scanning options
  // The third parameter is a callback called when a device is detected
  bleManager.startDeviceScan(null, null, (error, scannedDevice) => {
    if (error) {
      console.warn(error);
      return;
    }

    if (scannedDevice && scannedDevice.name === NAME) {
      console.log(scannedDevice.name, scannedDevice.rssi); // to find the device we need
      // hereinafter we will process RSSI
    }
  });
}
// Stop scanning if necessary
function stopScanning() {
  bleManager.stopDeviceScan();
}

function calculateDistance(rssi, measure = -69, multiplier = 2) {
  return Math.pow(10, (measure - rssi) / (10 * multiplier));
}

bleManager.startDeviceScan(null, null, (error, scannedDevice) => {
  if (error) {
    console.warn(error);
    return;
  }
  if (scannedDevice && scannedDevice.name === NAME) {
    const distance = calculateDistance(scannedDevice.rssi);
  }
});

const rssiValues = {}; // object for storing arrays of RSSI values

function addRssiValueAndGetAverage(deviceId, newValue, maxSize = 3) {
  if (!rssiValues[deviceId]) {
    rssiValues[deviceId] = []; // Initialize the array if this is the first value
  }
  const values = rssiValues[deviceId];
  values.push(newValue); // Add a new value

  // Remove the oldest value if the maximum array size is exceeded
  if (values.length > maxSize) {
    values.shift();
  }

  // Calculate the average value
  const averageRssi = values.reduce((acc, value) => acc + value, 0) / values.length;
  return averageRssi;
}

bleManager.startDeviceScan(null, null, (error, scannedDevice) => {
  if (error) {
    console.warn(error);
    return;
  }
  if (scannedDevice && scannedDevice.name === NAME) {
    const averageRssi = addRssiValueAndGetAverage(scannedDevice.id, scannedDevice.rssi);
    console.log(`Average RSSI value for device ${scannedDevice.name}: ${averageRssi}`);
  }
}); // Here you can use the average RSSI value to estimate the distance } });