Enums define a named set of constants (numeric or string). Literal types (union of specific values) often achieve the same intent more lightly and are usually preferred in modern TypeScript.
enum Status { Active, Inactive } creates numeric constants (0, 1); enum Role { Admin = 'ADMIN' } creates string constants. Enums generate runtime objects (they exist in the emitted JS). Literal union types — type Status = 'active' | 'inactive' — are purely compile-time, lighter, and integrate better with narrowing and JSON. as const turns an object/array into deeply readonly literal types, a common way to derive unions (type Keys = typeof OBJ[keyof typeof OBJ]). Many teams prefer string literal unions or const objects over enums to avoid enum's runtime footprint and quirks (numeric enum reverse mapping).
Instead of enum Env { Dev, Staging, Prod }, a test config uses type Env = 'dev' | 'staging' | 'prod' so values match the actual --env strings and narrow cleanly in switches.
Why do many TypeScript teams prefer type Status = 'open' | 'closed' over a string enum?