dry-refactoring

name	dry-refactoring
description	Guided workflow to eliminate copy-paste duplication detected by jscpd. Refactor clones using extract function, module, constant, or base class strategies.

dry-refactoring

Guided workflow to eliminate copy-paste duplication in source code using the repository-local jscpd configuration.

Prerequisites

First, run jscpd from the repository root with the project-local dependency so .jscpd.json is honored:

pnpm exec jscpd --reporters ai

For CI parity or a concise console summary, run:

pnpm exec jscpd

Do not use npx jscpd <path> in this repository: it can bypass the pinned workspace dependency and may ignore the repo-level exclusions for tests, fixtures, examples, generated output, and lockfiles.

Workflow

1. Run pnpm exec jscpd --reporters ai from the repository root
2. Parse each clone line to identify the two duplicated locations (file + line range)
3. Read both code fragments from the source files
4. Understand what the duplicated code does
5. Design a refactoring: extract a shared function, class, module, or constant
6. Apply the refactoring — update both locations and all other usages
7. Re-run pnpm exec jscpd --reporters ai to confirm the clone is eliminated
8. Repeat for remaining clones, highest-impact first

Refactoring Strategies

Extract function — when the duplicate is a block of logic:

// Before: same block in two places
// After: shared function called from both places

Extract module/utility — when the duplicate spans multiple files in different domains:

// Move shared logic to a shared utility file and import it

Extract constant or config — when the duplicate is repeated data or configuration.

Template/base class — when the duplicate is structural (e.g., repeated class shape).

Always ensure:

• All call sites are updated, not just the two reported by jscpd
• Tests still pass after refactoring
• The extracted abstraction has a clear, descriptive name

Tips

• Start with clones that have the highest line count — they have the most impact
• A clone between test files may indicate a missing test helper
• Clones across unrelated modules may signal a missing shared utility
• Prefer the repository's .jscpd.json thresholds and ignore rules before adding ad-hoc CLI flags