Prefer a union of literals over a TypeScript enum

Prefer a union of literals over a TypeScript enum

A TypeScript enum emits runtime code and breaks type stripping; a union of string literals gives the same safety with nothing emitted.

enum is one of the few TypeScript features that is not just types. It emits an object at runtime, so it cannot be erased, and Node's type stripping refuses the file.

A union of string literals is checked the same way and compiles to nothing.

// Bad
enum Status {
  Draft = "draft",
  Released = "released",
}

// Good
type Status = "draft" | "released";

When the values are needed at runtime, for a dropdown or a validator, derive the type from a constant list.

const STATUSES = ["draft", "released"] as const;
type Status = (typeof STATUSES)[number];

Declaration files that describe somebody else's enum are not yours to change.