ErrorHandlerService has zero dependency on Express — it's a plain
"map an error to {status, body}" service that works identically
behind any HTTP framework. It had no business living in a package
named express-tools.
Extracted HttpError, ErrorHandlerService, and ErrorHandlingResult
into a new packages/error-tools package (same tsc-build-to-dist
pattern as shared/express-tools). express-tools now only keeps the
actual Express-specific layer: ExpressServer, wrapAsyncHandler, and
createErrorMiddleware (which adapts ErrorHandlerService, imported
from error-tools, onto Express).
- packages/error-tools: new package, depends on shared + zod
- packages/express-tools: drops zod dependency, adds error-tools
dependency for error-middleware.ts's type import
- apps/api: adds error-tools dependency; app.ts, auth.service.ts,
require-auth.ts now import HttpError/errorHandlerService from
error-tools instead of express-tools
- apps/api/Dockerfile: adds COPY for packages/error-tools in the
runtime stage
- specs/error-handling.md, specs/backend-architecture.md, README.md
updated to reflect the new package split
Verified: pnpm lint, pnpm build (all packages, correct dependency
order), pnpm test (9/9 Mocha), pnpm test:bdd (5/5 Cucumber), full
Docker rebuild + compose up (no crash-loop), curl + browser checks
of /health, unknown-route 404, signup (201), duplicate-email 409
(code 4001 EMAIL_ALREADY_IN_USE) — all going through the moved
ErrorHandlerService/HttpError correctly.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Five more explicit review points, on the same PR branch.
## Every interface key commented
Audited all 6 interfaces in the codebase. Two had partially-commented
members (violates the "every key gets /** */" rule): AuthResult
(apps/api/auth.service.ts) and SafeUserProfile (packages/shared) — both
now fully commented. The other four (AuthTokenPayload,
AuthContextValue, ErrorHandlingResult, ApiErrorResponse) were already
compliant.
## Removed the Express namespace augmentation
apps/api/src/types/express.d.ts (renamed to express-request.augment.ts
in the last round) is gone entirely. requireAuth now attaches the
authenticated profile to `res.locals.userProfile` — Express's own
built-in per-request mechanism for exactly this — typed via a new
AuthLocals interface and `Response<unknown, AuthLocals>`, instead of a
project-wide `declare global` silently changing every Request's type
whether or not it went through the middleware.
## ErrorHandlerService confirmed framework-agnostic
It already had zero Express import. Documented this explicitly (in the
package's index.ts and the new backend-architecture.md spec) as a
deliberate split: ErrorHandlerService is framework-agnostic (would work
behind Fastify too), ExpressServer/createErrorMiddleware are the actual
Express integration layer.
## packages/express-tools: server init + route/middleware utilities
New ExpressServer class, modeled on the pattern shared as a reference
(adapted, not copied 1:1 — deliberately left out the reference's custom
runtime param-type-validation system, since zod already does that job
in this codebase and running two parallel validation mechanisms would
be redundant, not "propre"):
- setupCore() — the common cors/json/cookie-parser stack
- addRoute() — registers a route, warns+skips instead of silently
double-registering the same method+path
- addMiddleware() / mountRouter() / setErrorHandler()
- listen()
- .instance — the raw Express app, for supertest
Also added wrapAsyncHandler() — forwards a thrown/rejected error from an
async handler to next(err) automatically, removing the manual
try/catch/next(err) every route needed.
apps/api/src/app.ts now builds via ExpressServer (createServer(),
consumed by both server.ts's .listen() and createApp()'s .instance for
tests). auth.routes.ts's signup/login handlers use wrapAsyncHandler
instead of manual try/catch. cookie-parser/cors moved out of apps/api's
own dependencies entirely — they're express-tools' concern now.
## assertIsNever (packages/shared/src/tools/)
Exhaustiveness-check helper for switch/if-chains over a union: takes a
`never`-typed value and throws, so a forgotten case in a later-added
union member becomes a compile error instead of a silent runtime
fallthrough. Verified for real (not just written and assumed correct):
wrote a throwaway switch missing a case and confirmed `tsc` rejects it
with the exact expected error, then deleted the scratch file. No
existing switch/if-chain over a union in the codebase yet to retrofit
it into — noted as ready for when one appears (e.g. the not-yet-built
batch-cooking calculation module or recipe-import pipeline).
## specs/ updated
New specs/backend-architecture.md — ExpressServer, wrapAsyncHandler,
the res.locals decision (with the "why not declare global" reasoning
spelled out), assertIsNever. error-handling.md and
frontend-architecture.md cross-link to it instead of duplicating.
README covers the same, briefly.
## Verification
Full lint/mocha/cucumber/build green. Re-ran `node dist/server.js`
standalone (mirrors Docker, no tsx) after the ExpressServer refactor:
/health, a 404 (numeric 4040), and a real signup + GET /me round trip
confirming res.locals-based auth actually works at runtime, not just
that tsc accepts the types.
