---
name: a4-entry-points
description: How the two report editors are reached and dispatched between — kind decides the route, and why the A4 editor now needs Router + NomenclatureData context in tests
metadata:
  type: project
---

Phase 7 wired the A4 designer to real operator entry points. Three things here
are easy to get wrong later.

**Report `kind` decides the route, never a default.** `Main.jsx` fetches
`/api/reports/?name=notice_report` and branches: `kind === 'a4'` → dynamic
`import()` of `a4/print/printReport` and `printA4Report(report, data)`;
otherwise the existing `ReportPreviewModal`. "Design Notice" routes to
`/report-editor-a4` or `/report-editor` by the same field.

**Why it matters:** a matrix report opened in the mm editor reads its character
x/y as millimetres and looks like a corrupt layout rather than a routing bug —
a slow, confusing failure. The A4 editor's auto-load therefore filters on
`?kind=a4&name=...`, not name alone; verified against the real DB that
`?kind=a4&name=<a matrix report>` returns 0 rows.

**How to apply:** any new entry point that opens a saved report must resolve
`kind` before choosing an editor or a render path. Never assume a name implies
a kind.

**`A4ReportEditor` now requires two contexts.** It calls `useLocation`/
`useNavigate` (router-state auto-load) and `useNomenclatureData` (sample-data
fallback). Both throw outside their providers, so any jsdom test mounting the
whole editor needs `<MemoryRouter>` plus
`vi.mock('../../../../contexts/NomenclatureDataContext', ...)`. Mocking the
nomenclature hook rather than standing up the provider keeps the SSE client and
auth context out of tests that are really about drag geometry.

**Why:** adding these deps silently broke four existing `a4Guides` tests with
"useLocation() may be used only in the context of a <Router>" — the component
was fine, the harness was stale.

**`window.print()` is not gated by transient user activation** the way
`window.open` is, so an `await` before it is safe. The A4 print chunk is still
prefetched on hover/focus of the Print Notice button, purely to shorten the gap
on a slow station. This was reasoned, not verified in a real browser — if Print
Notice is ever reported as doing nothing on click, re-test that assumption
first.

Related: [[a4-print-path]], [[a4-designer-conventions]], [[testing-react]]