[Home](./index.md) > [@empathyco/x-components](./x-components.md) > [XPriorityBus](./x-components.xprioritybus.md) ## XPriorityBus class A default [XBus](./x-components.xbus.md) implementation using a [priority queue](./x-components.xpriorityqueue.md) as its data structure to prioritise the emission of events. The priorities are preconfigured based on event naming. **Signature:** ```typescript export declare class XPriorityBus implements XBus ``` **Implements:** [XBus](./x-components.xbus.md)<SomeEvents, SomeEventMetadata> ## Constructors

Constructor	Modifiers	Description
[(constructor)(config)](./x-components.xprioritybus._constructor_.md)		Creates a new instance of a [XPriorityBus](./x-components.xprioritybus.md).

## Methods

Method	Modifiers	Description
[emit(event, payload, metadata)](./x-components.xprioritybus.emit.md)		Emits an event. See [XBus.emit](./x-components.xbus.emit.md).
[on(event, withMetadata)](./x-components.xprioritybus.on.md)		Retrieves an observable for the event. See [XBus.on](./x-components.xbus.on.md).