Edwin van den Houdt
cf44bda0ce
8 template-generic skills in .claude/skills/ (new-feature, new-context, value-object, form-machine, bff-endpoint, mutation-command, ui-component, new-ssp), condensed from CLAUDE.md/ARCHITECTURE/fp-tea/ADRs and pointing at this repo's worked examples. CLAUDE.md gains a pointer. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
58 lines
2.8 KiB
Markdown
58 lines
2.8 KiB
Markdown
---
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name: bff-endpoint
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description: Add a screen-shaped read — backend endpoint returning a decision-enriched DTO, regenerated typed client, contracts DTO, adapter with parse boundary, application store, <app-async> in the page. Use for any new data a page needs.
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---
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# BFF-lite read endpoint (decision DTO)
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One screen = one endpoint returning everything that screen needs, **decisions
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included**. The FE renders the server's decisions; it never recomputes business
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rules (ADR-0001). Per rule choose: **decision flag** (server computes the boolean)
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or **config value** (server sends the threshold, FE applies it for instant feedback,
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server re-validates as authority).
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## Steps
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1. **Backend** (`backend/src/BigRegister.Api/`): minimal-API endpoint under `/api/v1`,
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wire DTO in `Contracts/`, rule in `Domain/` with a test in
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`backend/tests/BigRegister.Tests/`. Rejections are ProblemDetails (RFC 7807, 422).
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2. **Regenerate the client**: `npm run gen:api` — commits `backend/swagger.json` +
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`src/app/shared/infrastructure/api-client.ts` (CI has a drift check; never edit the generated file).
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3. **DTO** in `<context>/contracts/<name>.dto.ts` — plain interfaces/string-literal
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unions. Contracts import **nothing** (lint-enforced): no Angular, no aliases, no relative imports.
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4. **Adapter** in `<context>/infrastructure/<name>.adapter.ts` — the only place HTTP lives:
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```ts
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@Injectable({ providedIn: 'root' })
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export class DashboardViewAdapter {
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private client = inject(ApiClient);
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viewResource() { return resource({ loader: () => this.client.dashboardView() }); }
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}
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// The trust boundary: validate the untrusted shape AND map DTO → domain.
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export function parseDashboardView(json: unknown): Result<string, DashboardView> { … }
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```
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The mapping may read as an identity copy today — the point is the **types** differ,
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so the compiler forces a real mapping the moment the wire diverges.
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5. **Application store** exposes the resource as `RemoteData` (`fromResource`,
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combine sources with `map`/`map2`/`andThen` from `@shared/application/remote-data`).
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UI never imports infrastructure (lint-enforced).
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6. **Page** renders through `<app-async>` (`shared/ui/async`) — one of
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loading/empty/error/loaded by construction. Check all four states with the
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dev-only `?scenario=slow|loading|empty|error` toggle.
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## Worked example (trace one name through all layers)
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`dashboard-view`: `backend/src/BigRegister.Api` endpoint →
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`src/app/registratie/contracts/dashboard-view.dto.ts` →
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`src/app/registratie/infrastructure/dashboard-view.adapter.ts` (+ spec on `parseDashboardView`) →
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`src/app/registratie/application/big-profile.store.ts` → dashboard page.
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## Verify
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```bash
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cd backend && dotnet test && cd ..
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npm run gen:api && git diff --exit-code src/app/shared/infrastructure/api-client.ts
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npm test && npm run lint && npm run build
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```
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