TypeScript Enums and When to Use Them

What are Enums?

Enums let you define a set of named constants, making code more readable and intent clearer than magic strings or numbers.

Numeric Enums

enum Direction { Up, Down, Left, Right }
let move: Direction = Direction.Up; // 0

String Enums (Preferred)

enum Status {
  Active = "ACTIVE",
  Inactive = "INACTIVE",
  Banned = "BANNED",
}
const s: Status = Status.Active; // "ACTIVE"

Enums vs Union Types

// Often a union is simpler and lighter:
type Status = "active" | "inactive" | "banned";

	Enum	Union
Runtime code	Yes	No (erased)
Readability	Good	Good

FAQs

Enum or union type?

Prefer union types unless you need a runtime object. More in our TypeScript guides.

What is a const enum?

An enum inlined at compile time for zero runtime cost.