Tools/domain/testing/TestApp.ts

import AppProjections from "../AppProjections";
import AppQueries from "../AppQueries";
import DomainEvent from "../DomainEvent";
import DomainProjection from "../DomainProjection";
import EventStore from "../EventStore";

export class TestApp {
  readonly eventStore: InMemoryEventStore = new InMemoryEventStore();
  readonly projections: AppProjections = new AppProjections();
  readonly queries: AppQueries = new AppQueries(this.projections);

  constructor(history: DomainEvent<any>[] = []) {
    this.projections.getAll().forEach((projection) => {
      this.eventStore.subscribe(projection);
    });

    for (const event of history) {
      this.eventStore.append(event);
    }
  }
}
class InMemoryEventStore implements EventStore {
  private handlers: DomainProjection[] = [];
  private readonly events: DomainEvent<any>[] = [];

  async append(event: DomainEvent<any>): Promise<void> {
    this.events.push(event);
    for (const handler of this.handlers) {
      handler.handle(event);
    }
  }

  subscribe(projection: DomainProjection): void {
    this.handlers.push(projection);
  }

  async replay(): Promise<void> {
    throw new Error(
      "Replay is not relevant for InMemoryEventStore. Use append instead."
    );
  }

  getAllEvents(): DomainEvent<any>[] {
    return this.events;
  }
}