Remove null value field for Play Json

implicit class JsonImprovement(json: JsValue) {
    def withoutNull = {
      def internal(newJson: JsValue): JsValue = {
        newJson match {
          case JsObject(fields) =>
            if (fields.isEmpty) JsNull
            else {
              fields.foldLeft(new JsObject(Map()))((agg, field) =>
                field match {
                  case (name, JsArray(arrayValues)) => {
                    val seqJsonVal = arrayValues.map{ arrayValue =>
                      internal(arrayValue)
                    }
                    agg + (name, JsArray(seqJsonVal))
                  }
                  case (_, JsNull) => agg
                  case other@(name, value: JsArray) => {
                    value.value.map { insideVal =>
                      val nested = internal(insideVal)
                      agg + (name, nested)
                    }.foldLeft(Json.obj())((obj, a) => obj.deepMerge(a.as[JsObject]))
                  }
                  case (name, value: JsObject) => {
                    val nested = internal(value)
                    agg + (name, nested)
                  }
                  case other@(name, value) => agg + other
                })
            }
          case JsArray(arrayValues) => {
            arrayValues.map{ arrayValue =>
              val nested = internal(arrayValue)
              nested
            }.foldLeft(Json.arr()) ((obj, a) => obj.append(a))
          }
          case other => other
        }
      }
      internal(json)
    }
  }