[Home](./index.md) > [@empathyco/x-components](./x-components.md) > [XPriorityBus](./x-components.xprioritybus.md) > [(constructor)](./x-components.xprioritybus._constructor_.md) ## XPriorityBus.(constructor) Creates a new instance of a [XPriorityBus](./x-components.xprioritybus.md). **Signature:** ```typescript constructor(config?: { queue?: XPriorityQueue>; priorities?: Dictionary; emitCallbacks?: AnyFunction[]; defaultEventPriority?: number; }); ``` ## Parameters

Parameter	Type	Description
config	{ queue?: [XPriorityQueue](./x-components.xpriorityqueue.md)<SomeEvents, [XPriorityQueueNodeData](./x-components.xpriorityqueuenodedata.md)<SomeEvents, SomeEventMetadata>>; priorities?: Dictionary<number>; emitCallbacks?: AnyFunction\[\]; defaultEventPriority?: number; }	_(Optional)_ A configuration object to initialise the bus. - param config.queue - A [priority queue](./x-components.xpriorityqueue.md) to store the events. - param config.priorities - A Dictionary defining the priorities associated to a given string. - param config.emitCallbacks - A list of functions to execute when an event is emitted. - param config.defaultEventPriority - A default priority to assigned to an event.