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Node-YALC Overview

Node-YALC is the pure Node.js/TypeScript foundation of the YALC ecosystem. Unlike nestjs-yalc, which is tightly coupled to the NestJS dependency injection and module system, node-yalc provides framework-agnostic utilities, types, and base classes that can be used in any Node.js environment.

Philosophy​

The primary goal of node-yalc is to centralize core business logic, standard error definitions, and fundamental utilities so they can be shared across microservices, CLI tools, and background workers, regardless of the web framework being used.

It is designed to be:

  • Zero-Dependency (mostly): Keeps external dependencies to an absolute minimum to prevent dependency hell.
  • Framework Agnostic: Usable in Express, Fastify, NestJS, or raw Node scripts.
  • Highly Typed: Exposes rigorous TypeScript interfaces and types for the rest of the ecosystem.

Key Modules​

  • Errors: A standardized hierarchy of HttpError classes (e.g., BadRequestError, UnauthorizedError) that carry metadata and can be safely serialized across service boundaries.
  • Logger: A pure Pino wrapper that handles the formatting and configuration of JSON logs without relying on NestJS context.
  • Event Manager: Generic EventEmitter wrappers and interfaces used to define strong contracts for event-driven architectures.
  • Types: Shared TypeScript interfaces used across both ferrox-node and nestjs-yalc.

Integration with NestJS-YALC​

In a typical enterprise setup, node-yalc is included as a Git Submodule within the nestjs-yalc repository. nestjs-yalc then provides the "glue" (Interceptors, Providers, Dynamic Modules) to inject these pure Node.js constructs into the NestJS lifecycle.

For example, a BadRequestError thrown from a pure domain function (using node-yalc) is automatically caught by the YalcExceptionFilter (in nestjs-yalc) and transformed into a standardized HTTP 400 response.