How to make a web app for your own Bluetooth Low Energy device? Step 11

main.js

function disconnect() {
  if (deviceCache) {
    log('Disconnecting from "' + deviceCache.name + '" bluetooth device...');
    deviceCache.removeEventListener('gattserverdisconnected',
        handleDisconnection);

    if (deviceCache.gatt.connected) {
      deviceCache.gatt.disconnect();
      log('"' + deviceCache.name + '" bluetooth device disconnected');
    }
    else {
      log('"' + deviceCache.name +
          '" bluetooth device is already disconnected');
    }
  }

  characteristicCache = null;
  deviceCache = null;
}