Feature Skill

Implement features with strict layer ordering and module isolation.

Steps

1. Identify target module(s)

Before coding, determine:

• •Which module(s) does this feature belong to?
• •Default to ONE module unless strictly necessary
• •If it spans multiple modules, explain why and minimize coupling

2. Apply layer rules

Respect the strict layer order — never skip or reverse it:

Routes → Controllers → Services → Repositories → Models

• •Routes (routes/): Define HTTP endpoints, apply policy middleware
• •Controllers (controllers/): Handle HTTP req/res, call services, format responses via lib/helpers/responses.js
• •Services (services/): Business logic, call repositories, throw AppError for domain errors
• •Repositories (repositories/): Database access only, use Joi schemas for validation
• •Models (models/): Mongoose schema definition (*.model.mongoose.js) and Joi schema (*.schema.js)

3. Apply modularity rules

• •Isolate feature logic inside the module boundary
• •Avoid cross-module imports unless absolutely required
• •If shared code is needed:
  • •Place it in lib/helpers/ or lib/services/
  • •Provide explicit justification for why it must be shared
• •Keep these inside the module (modules/{module}/**):
  • •Controllers, services, repositories, models, schemas, policies, routes, tests

4. Use existing helpers

Before writing new utilities, check:

• •lib/helpers/responses.js — JSend response wrapper
• •lib/helpers/AppError.js — Custom error class for domain errors
• •lib/helpers/errors.js — Error formatting utilities
• •lib/helpers/joi.js — Shared Joi validation helpers
• •lib/middlewares/policy.js — Authorization middleware
• •lib/middlewares/model.js — Model middleware

5. Follow API response format

All API responses must use the JSend wrapper from lib/helpers/responses.js:

// Success
responses.success(res, 'task list')(data);
// Error
responses.error(res, 422, 'Unprocessable Entity', errors.getMessage(err))(err);

6. Run verify

npm run lint
npm test

Notes

• •Config is loaded from config/ and overridable via DEVKIT_NODE_* env vars
• •Authentication is handled via Passport JWT middleware — don't reimplement
• •All policies must use lib/middlewares/policy.js patterns