如何在播放 json 中创建一个空的 JsResult？

Question

I am writing an implicit reads returning JsResult[Seq[T]] based on a condition:

some_condition match{
     case Some(value) => // JsResult[Seq[T]]
     case _ => // returning an empty JsResult here of similar type?
}

What would be the way for return such JsResult ?

Answer 1

You will need to use the method validate , which returns JsResult . There are 2 case classes that inherits JsResult :

1. JsSuccess
2. JsError

Therefore you can consider the following example:

case class T()
implicit val reads = Json.reads[T]
val jsValue: JsValue = ...

jsValue.validate[Seq[T]] match {
  case JsSuccess(t, path) =>
    println(t)
  case JsError(errors) =>
    println(errors)
}