How to check whether a JsValue is null or Empty [Scala, Play]

Question

I am trying to write a simple utility to check whether a JsValue is null or empty. I have this:

def is_nullOrEmpty(x: JsValue): JsBoolean = {
  JsBoolean(
    (x) match {
      case _ => x == null
      case _ => x.toString().isEmpty  
    }
  )
}

I am fairly new to Scala + Play and I am not sure whether this is the correct way to go about.

Alternatively this:

def is_nullOrEmpty(x: JsValue) = x == null || x.toString().trim.isEmpty

Where I am also including .trim

Can you help?

Answer 1

You can use Option. Please try the following:

def is_nullOrEmpty(x: JsValue): JsBoolean = Option(x) match {
  case None =>
    JsFalse
  case Some(value) =>
    if (Json.stringify(value) == "") {
      JsFalse
    } else {
      JsTrue
    }
}

Or even easier in one liner:

def is_nullOrEmpty1(x: JsValue): JsBoolean = JsBoolean(Option(x).exists(Json.stringify(_) != ""))

Having said that, the check of an empty string is redundant, as elaborated at Why does JSON.parse fail with the empty string? and in many other posts.

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