Enums

Part of the TypeScript course

Some values come from a short, fixed list. An order is pending, shipped or delivered. A log line is debug, info, warn or error. A direction is up, down, left or right. Writing those as plain strings works right up until someone types "shiped", and then a comparison silently fails and the order sits in a state nothing handles.

An enum, short for enumeration, is a named set of the allowed values. You define the list once, refer to its members by name everywhere else, and a typo becomes a compile error instead of a mystery. ...