Edwin van den Houdt
cf570a8132
Move the authoritative business rules off the frontend into a real backend,
realising the BFF-lite + decision-DTO design (ADR-0001) that until now lived
only in static mock JSON.
Backend (backend/):
- ASP.NET Core (.NET 10) minimal API, contract-first, Swagger UI at /swagger.
- DDD Domain/ rules layer: profession derivation + applicable policy questions
(DiplomaRules), herregistratie eligibility + reason (HerregistratieRule),
scholing threshold (IntakePolicy), submit rejections + reference generation
(SubmissionRules). In-memory seeded data, ProblemDetails (RFC 7807) errors.
- 27 xUnit tests: rule units + endpoint integration incl. BRP no-address and
DUO not-found fallbacks and 422 submit paths.
Frontend (only infrastructure/ + contracts/ change, as the architecture promised):
- NSwag-generated typed client (api-client.ts), routed through Angular HttpClient
via a small fetch adapter so the ?scenario= interceptor still applies.
- GET adapters use resource({ loader: client.x }); submit commands call the client
and map ProblemDetails -> err. The hardcoded uren==0 / manual-diploma rules are
deleted (now server-side). Domain, stores, UI and format validators unchanged.
- Deleted the now-dead public/mock/*.json.
Tooling/docs:
- npm start proxies /api -> backend; npm run gen:api regenerates the client;
docker compose up runs both (bind mounts use :z for SELinux/Fedora).
- backend/README.md walkthrough: adding a policy question is a one-file backend
change, no FE change, no client regen. Updated CLAUDE.md + ARCHITECTURE.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
139 lines
7.7 KiB
Markdown
139 lines
7.7 KiB
Markdown
# CLAUDE.md
|
|
|
|
Agent guide for this repo. The _why_ lives in `docs/ARCHITECTURE.md`,
|
|
`docs/architecture/0001-bff-lite-decision-dtos.md`, and the learning guide
|
|
`docs/fp-tea-atomic-design.md` (FP + The Elm Architecture + atomic design); this
|
|
file is the _rules_. When a decision below and those docs disagree, the docs win —
|
|
update this file.
|
|
|
|
POC of a Dutch BIG-register self-service portal (healthcare professionals log in,
|
|
view their registration, apply for re-registration). Angular 22, standalone,
|
|
signals. Auth is faked; **data and business rules are served by a minimal ASP.NET
|
|
Core backend** (`backend/`, see its README — in-memory seeded, no DB) and consumed
|
|
through an NSwag-generated typed client. The FE renders the backend's decisions.
|
|
|
|
## Commands
|
|
|
|
```bash
|
|
npm start # ng serve (proxies /api → backend) → http://localhost:4200
|
|
npm test # vitest
|
|
npm run build # ng build (must stay green)
|
|
npm run storybook # component library by atomic layer
|
|
npm run gen:api # regenerate the typed client from the backend OpenAPI doc
|
|
docker compose up # run FE + backend together (Swagger at :5000/swagger)
|
|
cd backend && dotnet test # backend rule + endpoint tests
|
|
```
|
|
|
|
`.npmrc` sets `legacy-peer-deps=true` (Storybook's peer range lags Angular 22).
|
|
Do not run `npm audit fix --force` — it downgrades Angular 22→21. Dev-only
|
|
advisories are pinned via `package.json` `overrides`; the shipped bundle audits clean.
|
|
|
|
## The decisions (non-negotiable working agreements)
|
|
|
|
### 1. DDD: contexts then layers, dependencies point inward
|
|
|
|
`src/app/<context>/<layer>/`. Contexts: `shared`, `auth`, `registratie`,
|
|
`herregistratie`, `showcase` (teaching page, not a feature).
|
|
|
|
| Layer | Job | Angular allowed? |
|
|
| ----------------- | ----------------------------------------- | -------------------------------- |
|
|
| `domain/` | business rules + data types | **No — pure TS.** Has `.spec.ts` |
|
|
| `application/` | coordinate state/tasks (stores, commands) | yes (signals) |
|
|
| `infrastructure/` | where data comes from (HTTP adapters) | yes (HTTP) |
|
|
| `contracts/` | wire DTOs (the FE⇄BE seam) | no |
|
|
| `ui/` | how it looks (components, pages) | yes |
|
|
|
|
**Dependencies only point inward**: `ui → application → domain`; everyone may use
|
|
`shared`; never the reverse. Cross-context only `herregistratie → registratie → shared`,
|
|
`auth → shared`. Imports use aliases as direction statements: `@shared/* @auth/*
|
|
@registratie/* @herregistratie/*`. `domain/` imports nothing from Angular.
|
|
|
|
### 2. Atomic design: folder = layer
|
|
|
|
`shared/ui` atoms → molecules → organisms; `shared/layout` templates (`shell`,
|
|
`page-shell`); context `ui/` pages. Each level only uses levels below. A new page
|
|
should be **composition of existing blocks** — adding building blocks is the
|
|
exception, not the default. Atoms are thin wrappers over Utrecht/RHC CSS classes;
|
|
we own only a small typed `input()` API, the design system does the visuals.
|
|
|
|
### 3. State: make illegal states unrepresentable
|
|
|
|
Default reflex — **if you're about to add a second/third boolean to track state,
|
|
model a discriminated union instead.** Three tools, all in `shared/application`:
|
|
|
|
- **`RemoteData<E,T>`** (`remote-data.ts`) — `Loading | Empty | Failure{error} | Success{value}`.
|
|
Combine sources with `map`/`map2`/`map3`/`andThen` (Failure > Loading > Success).
|
|
Render it via the `<app-async>` molecule (`shared/ui/async`) — one of four
|
|
templates, mutually exclusive by construction. Default loading spinner/skeleton
|
|
is delay-gated (~250ms) so fast connections don't flash.
|
|
- **Elm-style store** (`store.ts` → `createStore(initial, reduce)`) — all state in
|
|
one Model; change only by `dispatch(msg)` → **pure** `reduce(model, msg)`. Models
|
|
are tagged unions (see `herregistratie.machine.ts`, `intake.machine.ts`). Templates
|
|
send messages, never mutate.
|
|
- **`Result<E,T>` + value objects** ("parse, don't validate") — raw input becomes a
|
|
branded type only via a parser returning `Result` (`registratie/domain/value-objects/`:
|
|
`Postcode`, `Uren`, `BigNummer`). Once you hold the type, never re-check it.
|
|
|
|
**Derive, don't store** what you can compute — e.g. the wizard's visible steps are
|
|
`visibleSteps(answers)`, not a stored field (`intake.machine.ts`).
|
|
|
|
**Side effects stay out of the reducer.** A _command_ (`application/submit-*.ts`)
|
|
does the HTTP, then dispatches a message describing the outcome. Reducer = "what the
|
|
new state is"; command = "go do it, then say what happened."
|
|
|
|
**Shared cross-page state = one root singleton.** Stores are `providedIn: 'root'`
|
|
(`BigProfileStore`, `SessionStore`). That single instance is the shared state — no
|
|
NgRx, no extra lib. Optimistic update pattern: `begin*` (flip pending) →
|
|
`confirm*` (clear + `resource.reload()`) / `rollback*` (undo).
|
|
|
|
### 4. BFF-lite + decision DTOs (ADR-0001)
|
|
|
|
`infrastructure/` is the **only** layer that touches the network — the
|
|
anti-corruption boundary. Each screen gets one screen-shaped endpoint returning a
|
|
decision-enriched DTO; **the FE renders decisions, it does not recompute business
|
|
rules.** Per rule, pick: _decision flag_ (server computes the boolean — e.g.
|
|
herregistratie eligibility) or _config value_ (server sends threshold, FE applies
|
|
for instant feedback, server re-validates as authority — e.g. scholing threshold).
|
|
FE keeps only **format** validation, never as authority.
|
|
|
|
DTO lives in `contracts/`; a hand-written `parse*`/`toDomain` in `infrastructure/`
|
|
validates the untrusted shape and maps DTO → domain. Wiring a real .NET backend
|
|
touches only `infrastructure/` + `contracts/` (see ARCHITECTURE §6). Server-owned
|
|
rules stay in `domain/*.policy.ts` as reference impl + unit test, marked server-owned,
|
|
but the FE doesn't call them.
|
|
|
|
### 5. Testing
|
|
|
|
Vitest. Co-locate `*.spec.ts` next to the unit. **Domain and pure logic must have a
|
|
spec** (reducers, combinators, `visibleSteps`, parsers, boundary `parse*` adapters).
|
|
Test the pure function directly — no Angular TestBed for domain. UI is exercised via
|
|
Storybook stories (`*.stories.ts` co-located, titled `Layer/Name`, a11y addon on),
|
|
not heavy component tests.
|
|
|
|
## Conventions
|
|
|
|
- Standalone components only; no NgModules. Signal inputs (`input()`), `inject()` over
|
|
constructor DI (constructor only for `effect()`/template-ref injection).
|
|
- Angular-native control flow `@if/@for`; native `httpResource` for fetching;
|
|
`withViewTransitions()` for page transitions (header/footer have stable
|
|
`view-transition-name`, excluded from the fade).
|
|
- Routes: lazy `loadComponent`, persistent `ShellComponent` parent, `canActivate:
|
|
[authGuard]` on protected routes (`app.routes.ts`).
|
|
- Theming is one import — `src/styles.scss` pulls the RHC palette; no hand-written theme.
|
|
- Scenario toggle: `?scenario=slow|loading|empty|error` on data pages
|
|
(`scenario.interceptor.ts`) to see every async state.
|
|
- Prettier; `.editorconfig`. tsconfig: `noImplicitReturns`,
|
|
`noPropertyAccessFromIndexSignature`, `noFallthroughCasesInSwitch`, `isolatedModules`.
|
|
|
|
## Adding a feature (recipe)
|
|
|
|
Domain first (types + pure rules + spec, no Angular) → infrastructure (adapter:
|
|
`httpResource` or command returning `Result`) → application (store if shared state;
|
|
union + pure reduce) → UI last (compose `shared/ui` atoms, wrap async in `<app-async>`,
|
|
dispatch messages). Worked example: the intake wizard (`herregistratie/`).
|
|
|
|
## Out of scope (POC, don't build unprompted)
|
|
|
|
Real auth/DigiD, real backend, i18n, NgRx, licensed Rijkshuisstijl font/logo,
|
|
runtime DTO validation on every endpoint, multi-tab session sync, OpenAPI codegen.
|