quality

Quality

Auto-use when: bug, error, fix, debug, not working, broken, test, failing

Works with: All skills - final verification gate

---

Debugging (5 Steps)

1. REPRODUCE

# Create failing test or clear steps
it('should not crash with null profile', () => {
  const user = { id: '1', profile: null }
  expect(() => getAvatar(user)).not.toThrow()
})

2. ISOLATE

# Find exact location
git log --oneline -10 -- path/to/file.ts
git blame -L 40,50 path/to/file.ts

3. IDENTIFY ROOT CAUSE

Why crash? → profile is null
Why null? → API returns null for new users
Why not handled? → Assumed profile always exists
ROOT CAUSE: Missing null handling

4. FIX (Minimal)

// Before
return user.profile.avatar.url

// After
return user.profile?.avatar?.url ?? '/default.png'

5. VERIFY

npx tsc --noEmit        # Types pass
npm test                # Tests pass
# Check similar patterns in codebase

---

Testing

TDD Flow

RED → Write failing test
GREEN → Minimal code to pass
REFACTOR → Clean up

Test Priority

P0: Happy path works
P0: Auth blocks unauthorized
P0: Ownership blocks others' data
P1: Validation rejects bad input
P1: Edge cases handled
P2: Error states work

Test Template

import { describe, it, expect, vi } from 'vitest'

describe('createPost', () => {
  it('creates for authenticated user', async () => {
    vi.mocked(auth).mockResolvedValue({ userId: 'user-1' })
    const result = await createPost({ title: 'Test' })
    expect(result.authorId).toBe('user-1')
  })

  it('rejects unauthenticated', async () => {
    vi.mocked(auth).mockResolvedValue({ userId: null })
    await expect(createPost({ title: 'Test' })).rejects.toThrow('Unauthorized')
  })
})

---

Verification Commands

# MUST pass before "done"
npx tsc --noEmit          # TypeScript
npm test                   # Tests
npm run lint              # Lint
npm run build             # Build

# Check for lazy patterns
grep -r "TODO\|FIXME" src/
grep -r ": any" src/
grep -r "console\.log" src/
grep -rE "mock|fake" src/

---

Definition of Done

□ tsc --noEmit = 0 errors
□ Tests pass
□ No TODO comments
□ No any types
□ No mock data
□ No console.log
□ All UI states handled
□ Error handling present

---

QA Fix (Batch)

When given a QA report, fix all issues:

1. Parse report for file:line references
2. Prioritize: P0/Critical first, then P1/High
3. Fix each with minimal targeted changes
4. Verify: npx tsc --noEmit + npm test
5. Report before/after summary

Rules: Stay scoped to report issues. Don't refactor adjacent code.

---

Red Flags (STOP)

If You See	Action
TODO:	Implement now
: any	Add types
mockData	Wire to API
console.log(error)	Show to user
Missing loading state	Add skeleton
Missing error state	Add error UI
catch {} (empty)	Handle error