TypeScript has discriminated unions if that's what you were thinking of https://www.typescriptlang.org/docs/handbook/2/narrowing.html#discriminated-unions http

TypeScript has discriminated unions if that's what you were thinking of https://www.typescriptlang.org/docs/handbook/2/narrowing.html#discriminated-unions https://www.typescriptlang.org/docs/handbook/2/narrowing.htm...