TypeScript Patterns I Use Every Day

Discriminated Unions

The single most powerful pattern in TypeScript. Model your state explicitly and let the type system guide the UI.

Branded Types

Prevent primitive obsession by branding strings and numbers. A UserId is not an OrderId even if both are strings.

Satisfies Operator

Added in TS 4.9, satisfies lets you validate a value against a type without widening it. Incredibly useful for config objects.