---
phase: 04-review-download-security
plan: 02
subsystem: ui
tags: [react, typescript, jszip, blob-download, clipboard, tailwind]

# Dependency graph
requires:
  - phase: 04-01
    provides: Wave 0 test stubs for ReviewStep (RED baseline)
  - phase: 02-generators
    provides: Generator functions used by OutputBlock consumers
provides:
  - src/utils/downloadFile.ts — pure Blob+anchor download utility
  - src/utils/downloadZip.ts — JSZip archive builder with Blob download
  - src/components/wizard/OutputBlock.tsx — reusable code block with copy and optional download buttons
affects:
  - 04-03 (ReviewStep will import all three artifacts)
  - 04-04 (security gate applied via OutputBlock disabled prop)

# Tech tracking
tech-stack:
  added:
    - jszip ^3.10.1 (runtime dependency — client-side ZIP generation)
  patterns:
    - Blob + URL.createObjectURL + anchor click for file download (no FileSaver dependency)
    - JSZip generateAsync({ type: 'blob' }) for ZIP bundle download
    - navigator.clipboard.writeText with useState feedback (2s "Copied!" label)
    - disabled prop gates both copy and download actions (SECU-01 pattern)

key-files:
  created:
    - src/utils/downloadFile.ts
    - src/utils/downloadZip.ts
    - src/components/wizard/OutputBlock.tsx
  modified:
    - package.json (jszip added to dependencies)
    - package-lock.json

key-decisions:
  - "No src/utils/index.ts barrel — direct imports keep test mock paths predictable (../../utils/downloadFile)"
  - "Do NOT install @types/jszip — JSZip 3.x ships its own TypeScript declarations (stale package 6 years old)"
  - "OutputBlock renders Download button conditionally on filename prop presence — not hidden, rendered when applicable"
  - "disabled prop passed as HTML disabled attribute to both Copy and Download buttons — visual opacity-40 communicates lock state"

patterns-established:
  - "Pattern: Blob download helper — create Blob, createObjectURL, hidden anchor click, revokeObjectURL immediately after click"
  - "Pattern: OutputBlock disabled gate — parent passes disabled={!acknowledged} to apply SECU-01 per-block"

requirements-completed: [DOWN-01, DOWN-02, DOWN-03, DOWN-04, DOWN-05, DOWN-06, CONF-03]

# Metrics
duration: 2min
completed: 2026-03-27
---

# Phase 4 Plan 02: Download Utilities and OutputBlock Summary

**Blob/anchor download utility, JSZip ZIP builder, and reusable OutputBlock component with clipboard copy and per-block disabled security gate**

## Performance

- **Duration:** 2 min
- **Started:** 2026-03-27T10:43:40Z
- **Completed:** 2026-03-27T10:45:30Z
- **Tasks:** 2
- **Files modified:** 5

## Accomplishments

- Created `downloadFile` utility using native Blob + createObjectURL + anchor pattern (no FileSaver dependency)
- Created `downloadZip` utility using JSZip generateAsync — installed jszip as the only new runtime dependency in phase 4
- Created `OutputBlock` reusable component with copy button (clipboard.writeText with 2s feedback), optional download button, and SECU-01 disabled gate via prop

## Task Commits

Each task was committed atomically:

1. **Task 1: Create downloadFile.ts and downloadZip.ts utilities** - `f948b86` (feat)
2. **Task 2: Create OutputBlock.tsx reusable component** - `e223e8b` (feat)

**Plan metadata:** (docs commit — see below)

## Files Created/Modified

- `src/utils/downloadFile.ts` — Pure browser download: Blob + createObjectURL + anchor click + revokeObjectURL
- `src/utils/downloadZip.ts` — JSZip ZIP builder: loops file entries, generateAsync blob, same anchor download pattern
- `src/components/wizard/OutputBlock.tsx` — Labelled code block with copy button (clipboard + 2s feedback), optional download button, disabled prop gate
- `package.json` — jszip ^3.10.1 added to dependencies
- `package-lock.json` — lock file updated

## Decisions Made

- No barrel file `src/utils/index.ts` — direct imports from specific utility files keep test mock paths predictable (the Wave 0 test file mocks `../../utils/downloadFile` and `../../utils/downloadZip` by exact path)
- `@types/jszip` intentionally omitted — JSZip 3.x ships its own TypeScript declarations; `@types/jszip` is 6 years stale and causes type conflicts
- OutputBlock Download button rendered conditionally on `filename` prop presence — if no filename, no download button; both Copy and Download always visible when applicable (never hidden while disabled)
- `disabled:opacity-40` Tailwind class communicates lock state visually without hiding buttons

## Deviations from Plan

None — plan executed exactly as written. Utility implementations match the specification in the plan verbatim. Build pre-existing TypeScript errors (in test files and vite.config.ts) were confirmed pre-existing and out of scope.

## Issues Encountered

`npm run build` surfaces pre-existing TypeScript errors in `*.test.ts` files (vitest globals not typed in tsconfig) and `vite.config.ts` (`test` property). These are known pre-existing issues unrelated to this plan's changes. TypeScript compilation of the new source files is clean (verified via `tsc --noEmit --skipLibCheck`).

## User Setup Required

None — no external service configuration required.

## Next Phase Readiness

- `downloadFile`, `downloadZip`, and `OutputBlock` are ready for ReviewStep to compose in plan 04-03
- ReviewStep.test.tsx remains RED (ReviewStep file does not exist yet — expected at this stage)
- All 11 other test files remain GREEN (88 tests passing)

---
*Phase: 04-review-download-security*
*Completed: 2026-03-27*