How to make a web app for your own Bluetooth Low Energy device? Step 10

main.js

function requestBluetoothDevice() {
  log('Requesting bluetooth device...');

  return navigator.bluetooth.requestDevice({
    filters: [{services: [0xFFE0]}],
  }).
      then(device => {
        log('"' + device.name + '" bluetooth device selected');
        deviceCache = device;

        // Added line
        deviceCache.addEventListener('gattserverdisconnected',
            handleDisconnection);

        return deviceCache;
      });
}

function handleDisconnection(event) {
  let device = event.target;

  log('"' + device.name +
      '" bluetooth device disconnected, trying to reconnect...');

  connectDeviceAndCacheCharacteristic(device).
      then(characteristic => startNotifications(characteristic)).
      catch(error => log(error));
}