From TypeScript Handbook on Enums: Enums are one of the few features TypeScript has which is not a type-level extension of JavaScript. In other words, TypeScript enums have their corresponsing runtime ...

enum（列挙型）は、意味のある定数の集合をひとつの型としてまとめるための構文です。 JavaやC#など静的型付け言語由来の機能で、TypeScriptでも同様に使われます。

It is commonly used in all languages. Initial value starts from 0 if we do not set any value. Takes only numeric values. enum keyword is used to declare the numeric type enum. We can assign any value ...