# Implementation Plan: Cancel Event from Event List

**Branch**: `018-cancel-event-list` | **Date**: 2026-03-12 | **Spec**: [spec.md](spec.md)
**Input**: Feature specification from `/specs/018-cancel-event-list/spec.md`

## Summary

Enable organizers to cancel events directly from the event list page via the existing ConfirmDialog. The `EventList.vue` `confirmDelete` handler must detect the organizer role and call `PATCH /events/{eventToken}?organizerToken=...` with `{ cancelled: true }` instead of the existing RSVP deletion flow. The ConfirmDialog message must differentiate organizer cancellation (severe, affects all attendees) from attendee RSVP cancellation.

## Technical Context

**Language/Version**: TypeScript 5.x, Vue 3 (Composition API)
**Primary Dependencies**: openapi-fetch, Vue Router, Vite
**Storage**: localStorage via `useEventStorage()` composable
**Testing**: Vitest (unit), Playwright + MSW (E2E)
**Target Platform**: Mobile-first PWA (all modern browsers)
**Project Type**: Web application (frontend-only change)
**Performance Goals**: N/A (no new endpoints, minimal UI change)
**Constraints**: No backend changes required; cancel-event API already exists
**Scale/Scope**: ~50 lines of logic change in EventList.vue, dialog message updates

## Constitution Check

*GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.*

| Principle | Status | Notes |
|-----------|--------|-------|
| I. Privacy by Design | PASS | No new data collected or stored |
| II. Test-Driven Methodology | PASS | Unit tests + E2E tests planned |
| III. API-First Development | PASS | Uses existing PATCH endpoint already in OpenAPI spec |
| IV. Simplicity & Quality | PASS | Extends existing delete flow, no new abstractions |
| V. Dependency Discipline | PASS | No new dependencies |
| VI. Accessibility | PASS | Reuses existing ConfirmDialog (already has aria-modal, alertdialog role, keyboard nav) |

All gates pass. No violations.

## Project Structure

### Documentation (this feature)

```text
specs/018-cancel-event-list/
├── plan.md              # This file
├── research.md          # Phase 0 output
├── data-model.md        # Phase 1 output (minimal — no new entities)
└── tasks.md             # Phase 2 output (/speckit.tasks command)
```

### Source Code (repository root)

```text
frontend/src/
├── components/
│   ├── EventList.vue         # PRIMARY CHANGE: confirmDelete handler + dialog message
│   └── ConfirmDialog.vue     # No changes needed
├── api/
│   ├── client.ts             # No changes needed (openapi-fetch client)
│   └── schema.d.ts           # Already has PATCH /events/{eventToken} types
└── composables/
    └── useEventStorage.ts    # No changes needed

frontend/e2e/
└── cancel-event-list.spec.ts # NEW: E2E tests for organizer cancellation

frontend/src/components/__tests__/
└── EventList.spec.ts         # EXTEND: Unit tests for organizer cancel flow
```

**Structure Decision**: Frontend-only change. All logic changes in `EventList.vue`. No new components, composables, or API endpoints.