@OnLibraryEvent

Overview

@OnLibraryEvent() registers a method as a listener for a client-side library domain event.

This decorator listens to events emitted by client library wrappers through library.emit(...).

Like other OpenCore decorators, it stores metadata first; binding happens during bootstrap.

Signature

@OnLibraryEvent(libraryName, eventName)

Arguments

• libraryName: string — Library identifier.
• eventName: string — Domain event name inside the library.

Handler Parameters

Handlers receive:

1. payload — The payload passed in library.emit(...).
2. meta — Event metadata:
   • libraryName
   • eventName
   • eventId (<libraryName>:<eventName>)
   • namespace
   • side ('client')

Example

@Controller()
export class InventoryUiProjection {
  @OnLibraryEvent('inventory', 'items:updated')
  onItemsUpdated(
    payload: { count: number },
    meta: LibraryEventMetadata,
  ) {
    // react to local client library domain updates
  }
}

Important Scope Rule

@OnLibraryEvent() listens only to library.emit(...) events.

It does not listen to transport bridge methods such as:

• emitExternal(...)
• emitNetExternal(...)
• emitServer(...)

Notes

• Client-only decorator.
• Useful for UI projections, local reactions, and decoupled feature modules.