dry-refactoring

dry-refactoring

Guided workflow to eliminate copy-paste duplication in source code. Use after running jscpd to detect clones.

Prerequisites

First, run jscpd to identify duplications:

npx jscpd@4.0.5 --reporters ai <path>

Workflow

1. Run jscpd with --reporters ai on the target path
2. Parse each clone line to identify the two duplicated locations
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 jscpd to confirm the clone is eliminated
8. Repeat for remaining clones, highest-impact first

Refactoring Strategies

Strategy	When
Extract function	Same logic repeated with different inputs
Extract constant	Same literal values repeated
Extract base class	Parallel class hierarchies with shared behaviour
Extract module	Shared utilities across multiple modules
Template method	Same algorithm structure, different steps