alternative-classes-with-different-interfaces

Refuse: 21 — Alternative Classes with Different Interfaces

Trigger (refuse when you see): Two classes do similar things but with mismatched method names and signatures — sortBy() vs orderUsing(), valueOf() vs evaluate().

Cost of leaving it in: Substitution becomes copy-paste; consumers can't treat the two interchangeably; abstraction over them is impossible.

Target shape after refactoring: Equivalent operations have equivalent signatures; a shared superclass or interface emerges naturally.

// Smellier:
class CSVExporter  { writeAll(rows) {} }
class JSONExporter { dump(data)     {} }

// Fresher:
class CSVExporter  implements Exporter { write(rows) {} }
class JSONExporter implements Exporter { write(rows) {} }

Apply refactorings: Change Function Declaration, Move Function, Extract Superclass