Function transformSingle

repos/effect/packages/effect/src/unstable/cli/Param.ts:2038–2053

(
  param: Param<Kind, A>,
  f: <X>(single: Single<Kind, X>) => Single<Kind, X>
)

) {
  const results: Array<A> = []
  const names = [single.name, ...single.aliases]
  const values = names.flatMap((name) => args.flags[name] ?? [])
  const count = values.length

  // Validate count constraints
  if (Predicate.isNotUndefined(options?.min) && count < options.min) {
    return yield* count === 0
      ? new CliError.MissingOption({ option: single.name })
      : new CliError.InvalidValue({
        option: single.name,
        value: `${count} occurrences`,
        expected: `at least ${options.min} value${options.min === 1 ? "" : "s"}`,
        kind: single.kind
      })
  }

  if (Predicate.isNotUndefined(options?.max) && count > options.max) {
    return yield* new CliError.InvalidValue({
      option: single.name,