Complexity Guardrails
Design to keep complexity low from day one.
Targets
- Cyclomatic complexity per function ≤ 7 (start splitting at 5)
- Function length ≤ 80 lines (aim for ≤ 30)
- One responsibility per function; one axis of variation per module
Tactics
- Use early returns and guard clauses; avoid deep nesting
- Extract branch bodies into named helpers
- Replace long if/else/switch with tables (maps) or strategies
- Separate phases: parse → validate → normalize → act
Signs to refactor now
- Hard-to-test code paths
- Repeated conditionals with subtle differences
- Mixed concerns (IO, validation, transformation) in one method