# knip - Find unused files, exports, dependencies
npx knip

# depcheck - Identify unused npm dependencies
npx depcheck

# ts-prune - Find unused TypeScript exports
npx ts-prune

# eslint - Check for unused variables
npx eslint . --report-unused-disable-directives

a) Run detection tools in parallel
b) Collect all findings
c) Classify by risk:
   - Safe: Unused exports, dependencies
   - Caution: May be used via dynamic imports
   - High Risk: Public APIs, shared utilities

a) Start with only "Safe" items
b) Remove one category at a time:
   1. Unused npm dependencies
   2. Unused internal exports
   3. Unused files
   4. Duplicate code
c) Run tests after each batch
d) Create a git commit for each batch

a) Identify duplicate components/utilities
b) Select the best implementation:
   - Most feature-complete
   - Best tested
   - Most recently used
c) Update all imports to use the selected version
d) Delete duplicates
e) Verify tests still pass

# Code Deletion Log

## [YYYY-MM-DD] Refactoring Operation

### Removed Dependencies
- package-name@version - Last used: Never, Size: XX KB
- another-package@version - Replaced by: better-package

### Deleted Files
- src/old-component.tsx - Replaced with: src/new-component.tsx
- lib/deprecated-util.ts - Functionality moved to: lib/utils.ts

### Consolidated Duplicate Code
- src/components/Button1.tsx + Button2.tsx -> Button.tsx
- Reason: Identical implementations

### Removed Exports
- src/utils/helpers.ts - Functions: foo(), bar()
- Reason: No references in codebase

### Impact
- Files deleted: 15
- Dependencies removed: 5
- Lines of code removed: 2,300
- Package size reduced: ~45 KB

### Testing
- All unit tests passed
- All integration tests passed
- Manual testing completed

// Remove unused imports
import { useState, useEffect, useMemo } from 'react' // Only useState is used

// Keep only used imports
import { useState } from 'react'

// Remove unreachable code
if (false) {
  // Will never execute
  doSomething()
}

// Remove unused functions
export function unusedHelper() {
  // No references in codebase
}

// Multiple similar components
components/Button.tsx
components/PrimaryButton.tsx
components/NewButton.tsx

// Consolidate into one
components/Button.tsx (using variant prop)

// Installed but never imported packages
{
  "dependencies": {
    "lodash": "^4.17.21",  // Never used
    "moment": "^2.29.4"    // Replaced by date-fns
  }
}

# 1. Roll back immediately
git revert HEAD
npm install
npm run build
npm test

# 2. Investigate the cause
# - What failed?
# - Was it a dynamic import?
# - Did the detection tool miss something?

# 3. Fix forward
# - Mark as "Do Not Remove"
# - Document why detection tool missed it
# - Add explicit type annotations

## Refactoring: Code Cleanup

### Summary
Dead code cleanup, removing unused exports, dependencies, and duplicates.

### Changes
- Removed X unused files
- Removed Y unused dependencies
- Consolidated Z duplicate components
- See docs/DELETION_LOG.md for details

### Testing
- [x] Build passes
- [x] All tests pass
- [x] Manual testing completed
- [x] No console errors

### Impact
- Package size: -XX KB
- Lines of code: -XXXX
- Dependencies: -X packages

### Risk Level
Low - Only verified unused code was removed

See DELETION_LOG.md for details.