Refactor & Cleanup

Improve the internal structure of the selected code without changing its observable behavior. All tests must pass before and after.

Before Starting

• Confirm the test suite is passing.
• Note the current coverage baseline.
• Identify the scope: single function, file, or module?

Refactoring Targets

Dead Code Removal

• Unused variables, imports, functions, and exports
• Commented-out code blocks (delete, don't leave as comments)
• Feature flags that are permanently enabled/disabled
• Unreachable branches

Duplication Reduction

• Repeated logic that can be extracted into a shared utility
• Copy-pasted blocks differing only in a parameter (extract with that parameter)
• Inline constants that appear in multiple places (extract to named constants)

Structure Improvements

• Functions over 50 lines → break into smaller, named steps
• Files over 800 lines → extract cohesive sub-modules
• Nesting deeper than 4 levels → extract early-return guards or helper functions
• Mixed concerns in one function → split into focused single-responsibility functions

Naming

• Rename variables/functions whose names don't match their behavior
• Replace magic numbers and strings with named constants
• Align naming with the domain language used elsewhere in the codebase

Constraints

• No behavior changes — refactoring is purely structural.
• One concern at a time — do not mix refactoring with feature work or bug fixes.
• Keep tests green — run the suite after each meaningful change.
• Don't add abstractions preemptively — extract only what has already proven to be duplicated (rule of three).

Output

After refactoring, summarize:

• What was removed (dead code, duplication)
• What was extracted (new utilities, constants)
• What was renamed and why
• Coverage before / after (should not decrease)