Complexity Guardrails

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