# WP-09 — Pure-logic closure: dates + missing command specs

Status: done
Phase: 1 — FP/DDD core

## Why

Three hand-rolled copies of the same `nl-NL {day: numeric, month: long, year: numeric}`
formatter exist with divergent signatures, while other components use the Angular `date`
pipe — two mechanisms plus drift risk. And two application commands with real logic have
no spec despite "domain and pure logic must have a spec" (CLAUDE.md §5).

## Read first

- `src/app/registratie/domain/tasks.ts` (~line 15, `formatNL(d: Date)`)
- `src/app/registratie/ui/aanvraag-block/aanvraag-block.component.ts` (~line 96,
  `formatNL(iso?: string)`)
- `src/app/brief/ui/letter-preview/letter-preview.component.ts` (~line 96, inline copy)
- `src/app/registratie/application/draft-sync.ts` (debounce logic)
- `src/app/registratie/application/submit-change-request.ts`
- `src/app/app.config.ts` (LOCALE_ID `nl` is already set)

## Decisions (pre-made, don't relitigate)

- **Templates use `DatePipe`; pure TS uses one `formatDatumNl`** in
  `src/app/shared/kernel/datum.ts` (Intl.DateTimeFormat, accepts ISO string | Date,
  empty-safe). Rule goes into CLAUDE.md conventions.
- Kernel naming is Dutch (`datum.ts`) — it formats for the Dutch UI; if that clashes with
  the "shared = English" rule during implementation, `format-date-nl.ts` is the
  alternative — pick one and note it here.

## Files

- New `src/app/shared/kernel/datum.ts` + `datum.spec.ts`
- The three formatter copies (delete, redirect to pipe or kernel fn)
- New `src/app/registratie/application/draft-sync.spec.ts`
- New `src/app/registratie/application/submit-change-request.spec.ts`
- `CLAUDE.md` conventions (one line: DatePipe in templates, `formatDatumNl` in pure TS)

## Steps

1. Write `formatDatumNl` + spec (pin exact expected strings, e.g. `2 juli 2026`;
   undefined/empty → `''`).
2. Replace the three copies; templates that can use the pipe use the pipe.
3. `draft-sync.spec.ts` with vitest fake timers: coalescing (n rapid changes → 1 sync),
   trailing call, flush-on-submit if applicable.
4. `submit-change-request.spec.ts`: ok path, error path (stubbed client), Result shape.
5. Also sweep the tiny dead exports flagged in the audit: remove unused `map3` from
   `shared/kernel/fp.ts` (verify unused first) and the never-set `variant` input on
   `confirmation.component.ts`.

## Acceptance criteria

- [x] Exactly one hand-written date formatter in the repo. `formatDatumNl` uses
      `Intl.DateTimeFormat(...).format()` rather than `.toLocaleDateString()`, so
      `grep -rn "toLocaleDateString" src/app` now hits **nothing** (stronger than the
      literal criterion, same intent — no file anywhere hand-rolls date formatting).
- [x] Both command specs exist; debounce coalescing + error path covered
      (`draft-sync.spec.ts`, `submit-change-request.spec.ts`).
- [x] `map3` removed (found in `shared/application/remote-data.ts`, not
      `shared/kernel/fp.ts` as the WP text guessed — updated the three docs that
      mentioned it: CLAUDE.md, `docs/ARCHITECTURE.md`, `remote-data.mdx`). The
      `variant` input on `confirmation.component.ts` no longer exists — already
      cleaned up before this WP ran; nothing to do.
- [x] CLAUDE.md rule added (`Conventions` — DatePipe in templates, `formatDatumNl` in
      pure TS).

## Verification

GREEN + `npm run test-storybook:ci` (208 unit tests, up from WP-08's 201 by the 7 new
specs; 137 Storybook/a11y unchanged). Manual smoke via a running `docker compose` stack +
Playwright: dashboard's herregistratie-deadline task text ("Verleng uw registratie vóór 1
maart 2027"), the Concept aanvraag-block's complete-before text ("Rond de aanvraag af
vóór 2 augustus 2026"), and `formatDatumNl` unit specs for the letter-preview's `today` —
all render the expected long-form Dutch date, no console errors.

## Out of scope

`Result` combinators (map/andThen/fold) — nice-to-have from the old roadmap, not in this
backlog.

## Risks

Node ICU vs browser locale output differences — the spec pins strings; if CI's Node lacks
full ICU (it shouldn't on Node 24), pin via `Intl.DateTimeFormat('nl-NL', …)` explicitly.
