Web Bluetooth / Device Disconnect (Async Await) Sample

Available in Chrome 55+ | View on GitHub | Browse Samples

The Web Bluetooth API lets websites discover and communicate with devices over the Bluetooth 4 wireless standard using the Generic Attribute Profile (GATT). It is currently partially implemented in Android M, Chrome OS, Mac, and Windows 10.

This sample illustrates the use of the Web Bluetooth API to disconnect and get notified from a disconnection of a nearby Bluetooth Low Energy Device after connecting to it. You may want to check out the Device Disconnect (Promises) sample.

Live Output











  
    
      
    
  

  
    
JavaScript Snippet

  

  
    
var bluetoothDevice;

async function onScanButtonClick() {
  let options = {filters: []};

  let filterService = document.querySelector('#service').value;
  if (filterService.startsWith('0x')) {
    filterService = parseInt(filterService);
  }
  if (filterService) {
    options.filters.push({services: [filterService]});
  }

  let filterName = document.querySelector('#name').value;
  if (filterName) {
    options.filters.push({name: filterName});
  }

  let filterNamePrefix = document.querySelector('#namePrefix').value;
  if (filterNamePrefix) {
    options.filters.push({namePrefix: filterNamePrefix});
  }

  bluetoothDevice = null;
  try {
    log('Requesting Bluetooth Device...');
    bluetoothDevice = await navigator.bluetooth.requestDevice(options);
    bluetoothDevice.addEventListener('gattserverdisconnected', onDisconnected);
    connect();
  } catch(error) {
    log('Argh! ' + error);
  }
}

async function connect() {
  log('Connecting to Bluetooth Device...');
  await bluetoothDevice.gatt.connect();
  log('> Bluetooth Device connected');
}

function onDisconnectButtonClick() {
  if (!bluetoothDevice) {
    return;
  }
  log('Disconnecting from Bluetooth Device...');
  if (bluetoothDevice.gatt.connected) {
    bluetoothDevice.gatt.disconnect();
  } else {
    log('> Bluetooth Device is already disconnected');
  }
}

function onDisconnected(event) {
  // Object event.target is Bluetooth Device getting disconnected.
  log('> Bluetooth Device disconnected');
}

function onReconnectButtonClick() {
  if (!bluetoothDevice) {
    return;
  }
  if (bluetoothDevice.gatt.connected) {
    log('> Bluetooth Device is already connected');
    return;
  }
  try {
    connect();
  } catch(error) {
    log('Argh! ' + error);
  }
}