DRY Consolidation

Systematic extraction of duplicated code into shared, tested abstractions.

When to Use This Skill

Use this skill when...	Use these instead when...
Multiple files have identical/near-identical code blocks	Single file needs cleanup → /code:refactor
Copy-pasted utility functions across components	Looking for anti-patterns without fixing → /code:antipatterns
Repeated UI patterns (dialogs, pagination, error states)	Functional refactoring of a file or directory → /code:refactor
Duplicated hooks or state management boilerplate	Structural code search only → ast-grep-search
Import blocks are bloated from repeated inline patterns	Linting/formatting issues → /lint:check

Context

• Target path: !echo "$1"
• Project type: !find . -maxdepth 1 \( -name "package.json" -o -name "Cargo.toml" -o -name "pyproject.toml" -o -name "go.mod" \)
• Source directories: !find . -maxdepth 1 -type d \( -name "src" -o -name "lib" -o -name "app" -o -name "components" -o -name "packages" \)
• Test framework: !find . -maxdepth 2 \( -name "vitest.config.*" -o -name "jest.config.*" -o -name "pytest.ini" -o -name "conftest.py" \)
• Existing shared utilities: !find . \( -path "*/lib/*" -o -path "*/utils/*" -o -path "*/shared/*" -o -path "*/common/*" -o -path "*/hooks/*" \) -type f -print -quit

Parameters

• $1: Path or directory to scan (defaults to src/)
• --scope: Focus on a specific extraction type: utilities, components, hooks, or all (default: all)
• --dry-run: Analyze and report duplications without making changes

Execution

Execute this 7-step consolidation workflow. Use TodoWrite to track each extraction as a separate task.

Step 1: Scan for duplicated patterns

Scan the target path for duplicated patterns. Search for these duplication signals:

Identical function bodies:

Grep for function/method signatures that appear in multiple files.
Look for identical multi-line blocks (3+ lines) across files.

Repeated inline patterns:

• Utility functions defined identically in multiple files (string truncation, date formatting, validation)
• Identical error handling blocks (try/catch patterns, error state JSX)
• Copy-pasted UI fragments (pagination controls, confirmation dialogs, loading states)
• Repeated hook/state management patterns (delete confirmation + mutation + handler)
• Duplicated import blocks that signal repeated inline implementations

Search strategy:

1. Use Grep to find repeated function names, variable patterns, and import clusters
2. Use Glob to identify files with similar structure (e.g., all *List.tsx, all *Detail.tsx)
3. Read candidate files to confirm duplication and measure scope

Step 2: Classify duplications

Group discovered duplications into extraction categories:

Category	Extract Into	Location Convention
Utilities	Pure functions	src/lib/utils/ or src/utils/
Components	Shared UI components	src/components/ui/ or src/components/shared/
Hooks	Custom React/Vue hooks	src/hooks/ or src/composables/
Types	Shared type definitions	src/types/ or alongside the abstraction

Follow the project's existing conventions for shared code location. If no convention exists, propose one based on the framework.

Step 3: Plan extractions

For each duplication cluster, plan the extraction:

1. Name the abstraction — Use a clear, descriptive name that reflects the shared behavior
2. Define the interface — Determine parameters needed to cover all usage variations
3. Choose the location — Follow project conventions for shared code placement
4. List all consumers — Identify every file that will be updated
5. Assess risk — Note any subtle differences between duplicated instances that need parameterization

Present the plan to the user before proceeding (unless --dry-run was not specified and the scope is clear).

Plan format:

## Extraction Plan

### 1. [Abstraction Name] → [target file path]
- Type: utility | component | hook
- Replaces: [N] identical blocks across [M] files
- Consumers: [list of files]
- Parameters: [any variations that need to be parameterized]
- Estimated lines saved: [N]

Step 4: Extract shared abstractions

Execute each planned extraction:

1. Create the shared abstraction with proper typing and documentation
2. Replace each instance in consumer files with an import + usage of the new abstraction
3. Handle variations — parameterize differences between instances rather than creating multiple abstractions
4. Update imports — add the new import, remove imports that were only needed for the inline version

Extraction order: Start with utilities (no dependencies), then components, then hooks (may depend on utilities/components).

Mark each extraction as completed in the todo list before moving to the next.

Step 5: Write tests

Write tests for each extracted abstraction:

Abstraction Type	Test Approach
Utility function	Unit tests covering all input variations, edge cases
UI component	Render tests, prop variations, accessibility
Custom hook	Hook testing with mock dependencies, state transitions
Type definitions	Type-level tests if applicable (tsd, expect-type)

Place test files adjacent to the abstraction or in the project's test directory, following existing conventions.

Step 6: Clean up dead code

After all extractions are complete:

1. Remove unused imports from all updated consumer files
2. Remove dead code — inline helper functions that are now replaced
3. Verify no orphaned references — search for any remaining references to removed code

Step 7: Verify all checks pass

Run the full verification suite:

TypeScript/JavaScript projects:

npx tsc --noEmit          # Type checking
npm run lint              # Linting (or biome/eslint directly)
npm run test              # Full test suite

Python projects:

ty check .                # Type checking
ruff check .              # Linting
pytest                    # Test suite

Rust projects:

cargo check               # Type checking
cargo clippy              # Linting
cargo test                # Test suite

All three must pass. If any fail, fix the issues before reporting completion.

Output Summary

After all phases complete, report:

## DRY Consolidation Summary

### Extractions
- [Abstraction Name] (type) — replaced N blocks in M files
- ...

### New Files Created
- path/to/new/file.ts — [description]
- ...

### Tests Added
- N tests across M test files

### Net Effect
- ~N lines of duplicated code consolidated
- N reusable abstractions created
- All verified: typecheck + lint + N passing tests

Agentic Optimizations

Context	Approach
Quick scan	Use --dry-run to see duplication report without changes
Focused extraction	Use --scope utilities to extract only utility functions
Large codebase	Scope to specific directory: /code:dry-consolidation src/components/
Post-extraction verify	`npx tsc --noEmit 2>&1
Test run (fast)	npm test -- --bail=1 --reporter=dot for quick pass/fail

See Also

• /code:refactor — Functional refactoring of a file or directory (pure functions, immutability, composition)
• /code:antipatterns — Detection-only analysis for code smells
• ast-grep-search — Structural code search for finding patterns