undefined.ts

import { createFail, Runtype, setupInternalRuntype } from './runtype'

/**
 * undefined
 */
// eslint-disable-next-line no-shadow-restricted-names
function undefinedRuntype(): Runtype<undefined> {
  return setupInternalRuntype<undefined>(
    (v, failOrThrow) => {
      if (v !== undefined) {
        return createFail(failOrThrow, 'expected undefined', v)
      }

      return v
    },
    { isPure: true },
  )
}

export { undefinedRuntype as undefined }