[Home](./index.md) > [@empathyco/x-components](./x-components.md) > [XPriorityBus](./x-components.xprioritybus.md) > [on](./x-components.xprioritybus.on.md) ## XPriorityBus.on() method Retrieves an observable for the event. See [XBus.on](./x-components.xbus.on.md). **Signature:** ```typescript on(event: SomeEvent, withMetadata?: boolean): typeof withMetadata extends true ? Observable, SomeEventMetadata>> : Observable>; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | event | SomeEvent | Event to retrieve the observable for. | | withMetadata | boolean | _(Optional)_ Option to retrieve an observable with extra data about the event. | **Returns:** typeof withMetadata extends true ? Observable<[SubjectPayload](./x-components.subjectpayload.md)<[EventPayload](./x-components.eventpayload.md)<SomeEvents, SomeEvent>, SomeEventMetadata>> : Observable<[EventPayload](./x-components.eventpayload.md)<SomeEvents, SomeEvent>> The emitter for the event passed.