In JavaScript, you can use event listeners to detect when a device is connected or disconnected from the user’s system. This can be useful when you want to perform specific actions based on the presence or absence of a particular device, such as a USB drive or a Bluetooth device.

To listen for these events, you can utilize the navigator.usb and navigator.bluetooth APIs, which provide access to the USB and Bluetooth devices connected to the user’s system.

Listening for USB Device Connection and Disconnection Events

To listen for USB device connection and disconnection events, you can use the navigator.usb.onconnect and navigator.usb.ondisconnect event listeners. Here’s an example:

navigator.usb.addEventListener('connect', (event) => {
  const device = event.device;
  console.log(`USB device connected: ${device.productName}`);
});

navigator.usb.addEventListener('disconnect', (event) => {
  const device = event.device;
  console.log(`USB device disconnected: ${device.productName}`);
});

In the above code, we are adding event listeners for the connect and disconnect events of the USB API. When a device is connected, the connect event is triggered and the connected device information can be accessed from the event.device property. Similarly, when a device is disconnected, the disconnect event is triggered.

Listening for Bluetooth Device Connection and Disconnection Events

For Bluetooth device connection and disconnection events, you can use the navigator.bluetooth.addEventListener function to register event listeners. Here’s an example:

navigator.bluetooth.addEventListener('deviceconnected', (event) => {
  const device = event.device;
  console.log(`Bluetooth device connected: ${device.name}`);
});

navigator.bluetooth.addEventListener('devicedisconnected', (event) => {
  const device = event.device;
  console.log(`Bluetooth device disconnected: ${device.name}`);
});

In the above code, we are registering event listeners for the deviceconnected and devicedisconnected events of the Bluetooth API. The connected or disconnected device information can be accessed from the event.device property.

Conclusion

By using event listeners in JavaScript, you can easily detect when a device is connected or disconnected from the user’s system. Whether you are working with USB or Bluetooth devices, these APIs provide a convenient way to listen for these events and perform specific actions based on their occurrence.

#JavaScript #EventListeners