Algebraic Data Types in TS: Indestructible...

Your payment flow has a status: string field? You're one typo away from a double charge. A silent "pednign" in production won't throw an error; it loses money. Algebraic Data Types (ADTs) in TypeScript let you model states where invalid data is compiler-illegal. Not just "unlikely." Forbidden. The problem: The bag of optionals // ❌ Everything is possible... including double charging interface PaymentState { status: string; transactionId?: string; errorMessage?: string; receiptUrl?: string; retry