QueryRepository

Defined in: packages/ddd-core/persistence/query-repository.abstract.ts:75

Base class for read-side (query) repositories.

Resolves a query via the abstract find method and receives an ICache instance. Subclasses annotate find() with the @FromCache decorator to serve cached results, bypass cache, or rehydrate snapshots into domain entities.

Examples

Creating a query repository with the FromCache decorator

@Injectable()
export class GetUserQueryRepository extends QueryRepository<GetUserQuery, User | null> {
  constructor(
    @Inject(CACHE_TOKEN) protected readonly cache: ICache<UserSnapshot>,
    @Inject(MIKRO_ORM_CLIENT) private readonly store: MikroOrmStore,
  ) {
    super(cache);
  }

  @FromCache<GetUserQuery, User | null>({
    keyFn: (query) => cacheKey('user', { id: query.userId }),
    hydrateFn: (cached) => User.fromJSON(cached as UserSnapshot),
    alwaysHydrate: true,
  })
  async find(query: GetUserQuery): Promise<User | null> {
    return this.store.em.findOne(User, { id: query.userId });
  }
}

Declaring rehydration once for the whole repository

@Injectable()
export class GetRoleQueryRepository extends QueryRepository<GetRoleQuery, Role | null> {
  constructor(
    @Inject(CACHE_TOKEN) cache: ICache<RoleSnapshot>,
    @Inject(MIKRO_ORM_CLIENT) private readonly store: MikroOrmStore,
  ) {
    super(cache, { hydrateFn: (cached) => Role.fromJSON(cached as RoleSnapshot) });
  }

  @FromCache<GetRoleQuery, Role | null>({
    keyFn: (query) => cacheKey(Role.aggregateName, { id: query.roleId }),
  })
  async find(query: GetRoleQuery): Promise<Role | null> { ... }
}