# QA Report: TypeScript 6.0 Upgrade

**Date**: 2026-03-11
**Branch**: Current working branch
**Scope**: TypeScript 5.9.3 → 6.0.1-rc upgrade (dev-dependency and config change only)

## Changes Under Test

- TypeScript bumped from 5.9.3 to 6.0.1-rc in root and frontend `package.json`
- `tsconfig.json`: `types: []` added, `DOM.Iterable` removed from `lib`
- `global.ResizeObserver` → `globalThis.ResizeObserver` in two test files
- `@typescript-eslint/utils` moved from dependencies to devDependencies
- Root `typescript` and `vite` moved from dependencies to devDependencies
- npm `overrides` added for typescript-eslint peer dep resolution

## Results

| # | Check | Status | Details |
|---|-------|--------|---------|
| 1 | Type Safety (`tsc --noEmit`) | **PASS** | Zero errors. Clean compilation with TS 6.0.1-rc. |
| 2 | Frontend Lint (ESLint) | **PASS** | 0 errors, 857 warnings. All warnings are pre-existing (testing-library, unicorn, security rules). No new warnings introduced. |
| 3 | Frontend Unit Tests (Vitest) | **PASS** | 158 test files passed, 5 skipped. 1871 tests passed, 90 skipped. Zero failures. |
| 4 | Frontend Build (Vite) | **PASS** | Production build completed in 9.23s. 2455 modules transformed. Output: 1,434 kB JS (420 kB gzip), 83 kB CSS. |
| 5 | Pre-commit Hooks (Lefthook) | **PASS** | All 6 hooks passed: check-yaml, actionlint, end-of-file-fixer, trailing-whitespace, dockerfile-check, shellcheck. Frontend-specific hooks skipped (no staged files). |
| 6 | Security Audit (`npm audit --omit=dev`) | **PASS** | 0 vulnerabilities in both frontend and root packages. The `overrides` field introduces no security regressions. |

## Pre-existing Items (Not Blocking)

- **857 ESLint warnings**: Existing `testing-library/no-node-access`, `unicorn/no-useless-undefined`, `security/detect-unsafe-regex`, and similar warnings. Not introduced by this change.
- **5 skipped test files / 90 skipped tests**: Pre-existing skipped tests (Security.test.tsx suite and others). Not related to this change.

## Scans Skipped (Out of Scope)

- **GORM Security Scan**: No model/database changes.
- **CodeQL Go Scan**: No Go code changed.
- **Docker Image Security Scan**: Prep work only, not a deployable change.
- **E2E Playwright**: Dev-dependency change does not affect runtime behavior.

## Verdict

**PASS**

All six verification checks passed with zero new errors, zero new warnings, and zero security vulnerabilities. The TypeScript 6.0.1-rc upgrade is safe to proceed.
