TypeScript Tips I Reach For Daily

You don't need advanced type gymnastics to get most of TypeScript's value. These few patterns cover the majority of my day-to-day.

as const for literal unions

const sizes = ["sm", "md", "lg"] as const;
type Size = (typeof sizes)[number]; // "sm" | "md" | "lg"

satisfies to keep inference

Validate a value against a type without widening it — you keep the precise literal types while still catching mistakes.

Prefer unknown over any

unknown forces you to narrow before use, which is exactly the safety you wanted.