Refactor code safely with testing

refactorskillsetup L2★121

What it does

Refactor code while preserving behavior strictly

Best for

Internal code quality improvements (structure, typing, naming) without touching external contracts or logic when behavior preservation is non-negotiable

Inputs

· source code files
· existing test suite
· refactoring scope definition

Outputs

· restructured code
· passing test results
· linting report

Requires

· eslint
· test runner (Jest/etc)

Preconditions

All existing tests must pass before refactoring; test files must exist for every service file

Failure modes

Modifying public APIs; deleting tests; test failures not resolved; importing unexported symbols

Trust signals

· strict behavior-preservation principle
· mandatory baseline verification
· per-step safety checklist