Best way to validate optional ISO time about valibot HOT 2 CLOSED

export function validateTime(config: Config) {
  // defaults
  const _required = config.required ?? !config.optional ?? false

  return pipe(
    string(),
    !_required ? minLength(0) : nonEmpty('Required field'),
    check((input) => {
      if (!_required && !input) return true
      return /^(?:0\d|1\d|2[0-3]):[0-5]\d$/u.test(input)
    }, 'Invalid time format'),
  )
}

import * as v from 'valibot';

// Time or undefined
const Schema1 = v.optional(v.pipe(v.string(), v.isoTime()));

// Time or empty string
const Schema2 = v.union([v.literal(''), v.pipe(v.string(), v.isoTime())]);