code: function makeUrl(s) {
    return R.ifElse(
      R.both(R.has('username'), R.has('password'))
    , R.always(`http://${s.username}:${s.password}@${s.url}:${s.port}`)
    , R.always(`http://${s.url}:${s.port}`)
    )(s)
  }
docs: :: {username: String, password: String, url: String, port: String} -> String