Skill: Auto Duplicate File Fixer (TS/JS + Python)

Purpose

Automate detection and removal of duplicate files/functions in TypeScript, JavaScript, and Python projects. Safely refactor imports, validate with tests, and deploy changes with zero risk of breaking the system.

Designed for daily incremental fixes that keep architecture clean without chaos.

Inputs

• project_root: Path to project
• mode: 'daily' | 'aggressive' | 'analysis' (default: 'daily')
• --dry-run: Preview only, don't modify

Outputs

• .duplicate-report.json: Detection results
• .keep-remove-map.json: Decision mapping (keep/remove)
• .refactor-log.json: Files changed, imports updated
• .validation-log.json: Test/lint/build results
• .deploy-log.json: Commit/PR status
• .pipeline-log.json: Full execution log

Pattern Standards (TS/JS)

• Named exports preferred over default exports
• Imports: absolute paths or aliases (no relative > 2 levels)
• 1 file = 1 responsibility
• Utility functions: centralize in src/utils or src/services
• No duplicate functions across src/helpers, src/utils, src/services

Naming convention:

src/
  utils/        # General utilities (helper.ts, formatter.ts)
  helpers/      # (DEPRECATED: merge to utils)
  services/     # Business logic (userService.ts, authService.ts)
  hooks/        # React hooks
  components/   # UI components
  constants/    # Constants

Pattern Standards (Python)

• PEP8 compliance
• All functions/classes: must have docstring
• No duplicate logic across modules
• Centralize utils in /common or /core package

Example structure:

src/
  common/       # Shared utilities (helpers.py, validators.py)
  core/         # Core business logic
  services/     # Service classes
  models/       # Data models

Procedure

Phase 1: Detect Duplicates

Command: npm run check <project> -- --format=json --min-tokens=50

Alternative (direct): node scripts/detect.js <project> --format=json --min-tokens=50

Process:

• Scan all .ts, .tsx, .js, .jsx, .py files
• Compute MD5 hashes → find identical files
• Use jscpd → find structural duplicates (80%+ similarity)
• Use AST → find function/class duplicates (Python)
• Output: .duplicate-report.json

Tools:

• jscpd: Copy-paste detection
• ts-morph / babel: AST parsing
• python ast: Python structural analysis

Phase 2: Decide (Keep/Remove)

Command: npm run decide <project> -- --report=.duplicate-report.json --strategy=test-coverage-first

Alternative (direct): node scripts/decide.js <project> --report=.duplicate-report.json --strategy=test-coverage-first

Decision ranking (highest score wins):

1. Test Coverage (×3): # of test cases / describe blocks
2. Import Count (×2): How many files depend on this
3. Type Definitions (+5 if present): Has interface/type annotations (TS only)
4. Naming Convention (+3): Follows src/ conventions

Example:

File A (helper.ts):
  - 5 test cases → 15 points
  - imported by 3 files → 6 points
  - has types → 5 points
  - follows convention → 3 points
  Total: 29 points

File B (helpers/util.ts):
  - 0 tests → 0 points
  - imported by 1 file → 2 points
  - no types → 0 points
  - doesn't follow convention → 0 points
  Total: 2 points

Decision: KEEP A, REMOVE B

Output: .keep-remove-map.json

Phase 3: Refactor Imports & Delete

Command: npm run refactor <project>

Alternative (direct): node scripts/refactor.js <project>

Process:

1. Find all files importing removed files
2. TS/JS: Update import paths (handle variants: relative, absolute, index files)
3. Python: Update import x and from x import y statements
4. Delete removed files
5. Update barrel files (index.ts, __init__.py)
6. Output: .refactor-log.json

Safety checks:

• Dry-run all import replacements first
• Preserve import semantics (named vs default)
• Handle circular dependencies

Phase 4: Validate

Command: npm run validate <project>

Alternative (direct): bash scripts/validate.sh <project>

Validation stack:

• Tests: npm run test:ci / pytest
• TypeCheck: tsc --noEmit
• Lint: eslint / flake8
• Build: npm run build

If ANY fails:

• Rollback via git checkout -- .
• Log errors in .validation-log.json
• Exit with status 1

Output: .validation-log.json

Phase 5: Deploy

Command: npm run deploy <project> -- --auto-merge

Alternative (direct): node scripts/deploy.js <project> --auto-merge

Process:

1. Check git status for changes
2. Stage all changes (git add -A)
3. Commit with message including file counts
4. If GitHub Actions: create PR via API
5. Output: .deploy-log.json

Commit message:

Auto-fix: Remove duplicates and refactor imports

Files deleted: 5
Imports updated: 12

Automated by auto-duplicate-fixer skill

Error Handling Protocol

On Test Failure:

git checkout -- .
# Log failure to validation log
echo '{"status": "failed", "reason": "tests-failed", "timestamp": "'$(date -Iseconds)'"}' >> .validation-log.json

On TypeScript Errors:

npx tsc --noEmit --pretty

On Build Failure:

• Log full error
• Rollback
• Report to stderr

On Conflict:

• Skip this group
• Continue with next
• Document in log

Usage

Daily Mode (Safe)

npm run daily /path/to/project

• Fixes 1-3 files per day
• Always runs full validation
• Safe for CI/CD

Aggressive Mode

npm run aggressive /path/to/project

• Fixes larger batches
• Use when you know codebase is stable

Analysis Only (Dry-Run)

npm run dry-run /path/to/project

• No files modified
• Preview what would be fixed
• Generate reports only

Manual Phases

# Detect only
npm run check /path/to/project

# View decisions
cat /path/to/project/.keep-remove-map.json

# Refactor
npm run refactor /path/to/project

# Validate
npm run validate /path/to/project

# Deploy
npm run deploy /path/to/project

Automation (Cron/Scheduled)

Schedule daily at 2 AM (requires git access):

# Add to crontab
0 2 * * * cd /path/to/project && npm run daily

# Or in GitHub Actions
name: Daily Duplicate Fix
on:
  schedule:
    - cron: '0 2 * * *'
jobs:
  fix:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - run: npm run daily
      - uses: peter-evans/create-pull-request@v4

Supported Languages

Language	Detection	Refactor	Validate
TypeScript	✅ AST + jscpd	✅ Import rewrite	✅ tsc + test
JavaScript	✅ AST + jscpd	✅ Import rewrite	✅ eslint + test
Python	✅ AST	✅ import rewrite	✅ pytest + flake8

Examples

Example 1: Duplicate Utilities

Before:
src/utils/format.ts (15 tests, imported 5 places)
src/helpers/formatter.ts (0 tests, imported 1 place)

Decision: KEEP src/utils/format.ts, REMOVE src/helpers/formatter.ts

Action:
- Update: src/services/user.ts
  import { format } from '../utils/format';

- Delete: src/helpers/formatter.ts
- Delete: src/helpers/index.ts (if becomes empty)

Example 2: Python Duplicates

Before:
core/validators.py (validate_email, validate_phone)
utils/helpers.py (validate_email, validate_phone)

Decision: KEEP core/validators.py, REMOVE utils/helpers.py

Action:
- Update: services/user.py
  from core.validators import validate_email

- Delete: utils/helpers.py

Logs & Debugging

Check any phase's logs:

cat .duplicate-report.json     # What was found
cat .keep-remove-map.json      # What will be kept/removed
cat .refactor-log.json         # What was changed
cat .validation-log.json       # Test results
cat .deploy-log.json           # PR/commit status
cat .pipeline-log.json         # Full execution timeline

Caveats

• Circular imports: Will be detected pre-refactor
• Dynamic imports: May not be rewritten (manual check needed)
• Large projects: Consider aggressive mode for speed
• Python type hints: Optional, but recommended for better decisions

Requirements

• Node.js >= 16
• npm
• git
• jscpd (auto-installed)
• pytest / tox (Python projects)
• TypeScript compiler (TS projects)

Install script:

npm install