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Architecture

NestJS-YALC is structured as a modular monorepo, providing a bridge between raw Node.js utilities and the NestJS dependency injection system.

The Bridge Pattern​

At its core, NestJS-YALC acts as an adapter layer over @node-yalc. While @node-yalc provides pure TypeScript/Node.js classes and functions (like loggers, error types, and generic event emitters), @nest-yalc-2 wraps these into NestJS paradigms:

  • Providers (@Injectable): Core utilities are exposed as injectable services.
  • Dynamic Modules: Configurations are passed via .forRoot() or .forRootAsync() patterns.
  • Interceptors & Filters: Generic error types from @node-yalc are caught and mapped to proper HTTP/GraphQL responses via NestJS Exception Filters.
flowchart TD
    subgraph "Your Application"
        AppController[AppController]
        AppService[AppService]
    end
    
    subgraph "NestJS-YALC (@nest-yalc-2/*)"
        YalcLoggerModule[YalcLoggerModule]
        YalcExceptionFilter[YalcExceptionFilter]
        CrudGen[CrudGen Decorators]
    end

    subgraph "Core Node Utilities (@node-yalc/*)"
        PinoWrapper[Pino Logger Wrapper]
        BaseError[Base HttpError]
        CoreTypes[Core Interfaces]
    end

    AppController --> YalcLoggerModule
    AppService --> CrudGen
    YalcLoggerModule --> PinoWrapper
    YalcExceptionFilter --> BaseError

Module Taxonomy​

NestJS-YALC modules can be categorized into three main layers:

1. Infrastructure Layer​

Modules that deal with the underlying system and external boundaries.

  • @nest-yalc-2/logger
  • @nest-yalc-2/observability
  • @nest-yalc-2/errors
  • @nest-yalc-2/sentinel

2. Data & Persistence Layer​

Modules that handle data storage, retrieval, and mapping.

  • @nest-yalc-2/database
  • @nest-yalc-2/crud-gen
  • @nest-yalc-2/data-loader
  • @nest-yalc-2/audit

3. Communication Layer​

Modules that handle inter-service communication and APIs.

  • @nest-yalc-2/graphql
  • @nest-yalc-2/api-strategy
  • @nest-yalc-2/kafka
  • @nest-yalc-2/event-manager

Workspace Organization​

The repository relies on standard npm/yarn workspaces (or tools like Turborepo/Nx, depending on your setup) to manage the internal dependencies between @nest-yalc-2/ packages. When building an application, you should depend on the specific packages rather than the entire collection to keep your bundle size minimal.