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Design for Extraction ​

Design your TypeScript code so deterministic extraction can consistently detect each Component and Link in CI.

Why code design affects extraction accuracy ​

Deterministic extraction reads static types, decorators, and class/method structure from your code and your Extraction Config. When code follows a stable Convention, extraction produces repeatable results.

When code does not follow a stable Convention, extraction can miss Components or produce uncertain Links.

In the ecommerce demo app, event publishing uses the @EventPublisherContainer decorator:

typescript
import { EventPublisherContainer } from '@living-architecture/riviere-extract-conventions'
import { eventBus, OrderPlaced } from './events'

@EventPublisherContainer
export class OrderEventPublisher {
  publishOrderPlaced(event: OrderPlaced): void {
    eventBus.emit(event.type, event)
  }
}

This design gives extraction a typed Event publisher method and a typed Event argument, which improves Link detection.

View source in ecommerce-demo-app →

Golden Path conventions with examples ​

The Golden Path uses shared conventions so extraction can map code to Components and Links without AI.

1) Event classes use @Event ​

typescript
import { Event } from '@living-architecture/riviere-extract-conventions'

@Event
export class OrderPlaced {
  readonly type = 'OrderPlaced'
}

2) Event handlers declare subscribed events ​

typescript
import { EventHandlerContainer } from '@living-architecture/riviere-extract-conventions'

@EventHandlerContainer
export class PaymentCompletedHandler {
  readonly subscribedEvents = ['PaymentCompleted']

  handle(event: PaymentCompleted): void { /* ... */ }
}

3) Connection config declares event publishers ​

The ecommerce demo app extraction config declares event publishers at the top-level connections key:

json
{
  "connections": {
    "eventPublishers": [
      {
        "fromType": "eventPublisher",
        "metadataKey": "publishedEventType"
      }
    ]
  }
}

This works with the default conventions config where the eventPublisher custom type extracts publishedEventType from the publish method parameter type.

View config in ecommerce-demo-app →

Migration guide from legacy patterns ​

Use an incremental migration so extraction continues to work while conventions are adopted.

Step 1: Add Event conventions to code ​

  • Add @Event to Event classes
  • Add @EventHandlerContainer to handler classes (with subscribedEvents)
  • Add @EventPublisherContainer to publisher classes

Step 2: Configure conventions-based publisher detection ​

Add connections.eventPublishers to declare how event publishers are detected:

json
{
  "connections": {
    "eventPublishers": [
      {
        "fromType": "eventPublisher",
        "metadataKey": "publishedEventType"
      }
    ]
  }
}

This works with the default conventions config where the eventPublisher custom type extracts publishedEventType from the publish method parameter type.

See Also ​