Bluetooth

Entry point to Web Bluetooth functionality — available as navigator.bluetooth.

Since nx.js has no permission-chooser UI, requestDevice() scans for nearby BLE devices and resolves with the first device matching the filters (scanning for up to 15 seconds before rejecting with NotFoundError).

Device discovery on Switch

The Switch's application BLE scanner is filter-based (there is no unfiltered scan like browsers use), which constrains how devices can be discovered:

• Advertised service UUID (recommended): every UUID in the filters' services and in optionalServices is scanned for; devices advertising one of them are found, then name/namePrefix filters are applied.
• manufacturerData filters map onto the system's manufacturer-data scan, but the system only matches payloads whose first byte after the company identifier is 0x01 — most third-party devices won't match.
• Known address (nx.js extension): requestDevice({ deviceId: 'aa:bb:cc:dd:ee:ff' }) skips scanning entirely and connects directly (an unfiltered low-level scan primes the stack's device cache first, so this works even for devices that advertise no service UUIDs).

Example

// Connect to a Niimbot label printer by address and use its serial
// service — the same GATT flow as Chrome's Web Bluetooth:
const device = await navigator.bluetooth.requestDevice({
  deviceId: '12:0c:01:e6:59:cf',
  optionalServices: ['e7810a71-73ae-499d-8c15-faa9aef0c3f2'],
});
const server = await device.gatt.connect();
const service = await server.getPrimaryService(
  'e7810a71-73ae-499d-8c15-faa9aef0c3f2',
);
const chars = await service.getCharacteristics();

See

https://developer.mozilla.org/docs/Web/API/Bluetooth

Extends

• EventTarget

Methods

addEventListener()

Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

Parameters

Returns

void

Inherited from

EventTarget.addEventListener

See

https://developer.mozilla.org/docs/Web/API/EventTarget/addEventListener

dispatchEvent()

Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

Parameters

Returns

boolean

Inherited from

EventTarget.dispatchEvent

See

https://developer.mozilla.org/docs/Web/API/EventTarget/dispatchEvent

getAvailability()

Resolves with true when Bluetooth LE is available on this system.

Returns

Promise<boolean>

See

https://developer.mozilla.org/docs/Web/API/Bluetooth/getAvailability

removeEventListener()

Removes the event listener in target's event listener list with the same type, callback, and options.

Parameters

Returns

void

Inherited from

EventTarget.removeEventListener

See

https://developer.mozilla.org/docs/Web/API/EventTarget/removeEventListener

requestDevice()

Scans for a nearby Bluetooth LE device matching the provided filters.

Parameters

Returns

Promise<BluetoothDevice>

See

https://developer.mozilla.org/docs/Web/API/Bluetooth/requestDevice