scala - scalaJS から読み取った upickle - upickle.Invalid$Data: String (data: 1)

Question

ScalaJS から。

import upickle.default._
import scala.scalajs.concurrent.JSExecutionContext.Implicits.queue

case class Post(userId: Long, id: Long, title: String, body: String)

@JSExport
def posts() : Future[Seq[Post]] = {
  val txt = """[{
    "userId": 1,
    "id": 1,
    "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
    "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
  }]"""

  val p = read[Seq[Post]](txt)

  println(p)

  p

}

pp onFailure {
  case x => println(x)
}

println(x) 出力: upickle.Invalid$Data: 文字列 (データ: 1)

それを機能させる方法は？

更新/同期: https://github.com/lihaoyi/upickle-pprint/issues/154