typescript-exhaustive-switch

Exhaustive switch statements in TypeScript are enforced by assigning the switched value to a `never` typed variable in the default case, which triggers a compile-time error if any union member or enum value is missing.

The best way to catch missing cases when refactoring TypeScript discriminated unions is adding a default case that assigns the switched value to a `never` type, failing fast at compile time instead of causing runtime bugs.

TypeScript does not warn about unhandled enum values because standard switch statements lack inherent exhaustiveness checking; you must manually add a default branch assigning the value to `never` to trigger a compile-time error.

Yes, exhaustive switch checking works with string literal unions in TypeScript by applying the same `never` type check in the default case to ensure every possible string variant is explicitly handled during compile-time type checking.

You need to use the TypeScript `never` type for code safety when switching over discriminated unions or enums during feature development, ensuring newly added variants produce a clear compile-time failure pointing to the missing case.