add-react-page

Add React Page

The frontend slice. Read .agents/rules/frontend/shared.md plus the app file (frontend/admin.md / frontend/dashboard.md) — the two apps deliberately diverge:

Shared everywhere: types are hand-written (no codegen); apiFetch<T> from @/lib/api-client; cn() from @/lib/cn; env.apiBase from runtime /config.json; CVA components/ui + components/list primitives; Tailwind v4 CSS-first (tokens in src/styles/globals.css); toast from sonner; pages are named exports; placeholderData: keepPreviousData (v5).

Step 1 — API module (src/api/{resource}.ts)

Hand-write the DTO/param/input types and thin apiFetch functions.

// admin
import { apiFetch } from "@/lib/api-client";
import type { PagedResponse } from "@/lib/api-types";
const BASE = "/api/v1/{module}/{resources}";

export type {Resource}Dto = { id: string; name: string; /* … */ };

export async function search{Resources}(p: { pageNumber?: number; search?: string } = {}) {
  const q = new URLSearchParams();
  q.set("PageNumber", String(p.pageNumber ?? 1));
  q.set("PageSize", "10");
  if (p.search?.trim()) q.set("Search", p.search.trim());
  return apiFetch<PagedResponse<{Resource}Dto>>(`${BASE}/search?${q}`);
}
export async function create{Resource}(input: Create{Resource}Input) {
  return apiFetch<{ id: string }>(BASE, { method: "POST", body: JSON.stringify(input) });
}

(dashboard: inline type PagedResponse<T> = …, inline the path, camelCase params, mutations often return Promise<string>.)

Step 2 — Page (src/pages/{area}/...tsx, named export)

export function {Resource}ListPage() {
  const [search, setSearch] = useState("");           // debounce → reset page to 1 on change
  const [pageNumber, setPage] = useState(1);
  const query = useQuery({
    queryKey: ["{resources}", { pageNumber, search }],   // hierarchical; params object last
    queryFn: () => search{Resources}({ pageNumber, search: search || undefined }),
    placeholderData: keepPreviousData,
  });
  // render with components/ui/* + components/list/* (admin: PageHeader/Field…; dashboard: Entity* family)
}

Step 3 — Mutation (race-safe mutate(arg))

Pass per-call data through mutate(arg); read it from the callback variables — never from a closed-over render variable.

const qc = useQueryClient();
const createMut = useMutation({
  mutationFn: (input: Create{Resource}Input) => create{Resource}(input),
  onSuccess: () => { toast.success("Created"); qc.invalidateQueries({ queryKey: ["{resources}"] }); },
  onError: (e) => toast.error(e instanceof ApiRequestError ? e.message : "Failed"),
});
// admin: const form = useForm({ resolver: zodResolver(schema) });  form.handleSubmit(v => createMut.mutate(v))
// dashboard: controlled useState fields; onSubmit(e){ e.preventDefault(); createMut.mutate(payload); }

If you need to track the in-flight item (e.g. a per-row busy state), use onMutate: (arg) => setBusyId(arg) reading the mutate(arg) value (pattern: admin/src/pages/settings/sessions.tsx).

Step 4 — Register the route (routes.tsx)

const {Resource}ListPage = lazyNamed(() => import("@/pages/{area}/list"), "{Resource}ListPage");
// admin — under AppShell.children, gated:
{ path: "{resources}", element: <RouteGuard perms={[{Module}Permissions.{Resources}.View]}><{Resource}ListPage /></RouteGuard> },
// dashboard — under AppShell.children, suspense only:
{ path: "{area}/{resources}", element: withSuspense(<{Resource}ListPage />) },

Step 5 — (admin only) mirror the permission

Add the constant to src/lib/permissions.ts ({Module}Permissions.{Resources}.View = "Permissions.{Resources}.View"), and a PERMISSION_CATALOG entry if it belongs in the Role editor. See add-permission.

Step 6 — Playwright test (tests/{area}/{resource}.spec.ts)

test.beforeEach(async ({ page }) => {
  // admin: seedAuthedSession(page, { ...TEST_USER, permissions: [...ADMIN_PERMS] }); await installAdminShellMocks(page);
  // dashboard: await seedAuthedSession(page, TEST_USER); await installShellMocks(page);
  await mockJsonResponse(page, "**/api/v1/{module}/{resources}**", paged([SAMPLE]));   // page mocks AFTER shell mocks
});

Use mockProblemDetails(...) for error states. Dashboard: scope row assertions with .last() / dialog scoping (lists render mobile + desktop copies → strict-mode double match).

Step 7 — Verify

cd clients/{app} && npm run lint && npm run test:e2e

Checklist

• API module: hand-written types, apiFetch, correct param casing per app (Pascal=admin, camel=dashboard)
• Page is a named export; useQuery key hierarchical + placeholderData: keepPreviousData
• Mutation passes data via mutate(arg), invalidates in onSuccess
• Route via lazyNamed; admin wraps in <RouteGuard perms>, dashboard in withSuspense
• (admin) permission mirrored in lib/permissions.ts
• Playwright test: seed + shell mocks + page mocks; lint + test:e2e green