mkenum: make enum type in javascript

Install

Install via npm package:

npm i mkenum

Usage

import makeEnum, {type IEnum} from 'mkenum'

const Env = makeEnum('dev', 'stg', 'prod') // return {dev: 'dev', stg: 'stg', prod: 'prod'}
type Env = typeof Env.$ // type 'dev' | 'stg' | 'prod'
const dev = Env.dev // type 'dev'

Caveats

• .$ on the returned object is type-only. It exists in the type signature for convenience (typeof Env.$), but there is no concrete value at runtime — accessing Env.$ will return undefined.

• If '$' is one of the enum values, typeof Env.$ resolves to the literal type '$' instead of the union of all values. In that case, derive the union with keyof typeof instead:

  const Env = makeEnum('$', 'dev', 'prod')
  type Env = typeof Env[keyof typeof Env] // type '$' | 'dev' | 'prod'