create custom JsObject out of case class - scala

Question

im getting in my api some case class that looks like this:
case class UserUpdate(
name: Option[String],
age: Option[String],
city: Option[String])
from this case class I need to build update json for mongo that looks like:
{"basicInfo.name": "new nameeee","age.vatId": "23"}
since all the fields are optional, I need to go over the fields and build it by the ones that are defined.
so I did something like this:
val updateAsMap = Json.toJson(userUpdateObj).as[JsObject]
.fields.map(fieldTpl => fieldTpl.copy(_1 = s"basicInfo.${fieldTpl._1}")).toMap
val userUpdateJson = Json.toJson(updateAsMap)
val query = json("userId" -> userId)
val update = json("$set" -> userUpdateJson)
is there a better suggestion, something that will look more elegant?

Answer 1

One option could be to convert UserUpdate to an intermediary case class, say MongoModel, and then convert MongoModel to JSON. For example,
import play.api.libs.json._
case class MongoModel(
`basicInfo.name`: Option[String] = None,
`age.vatId`: Option[String] = None
)
object MongoModel {
implicit val codec = Json.format[MongoModel]
}
case class UserUpdate(
name: Option[String] = None,
age: Option[String] = None,
city: Option[String] = None
) {
def toMongoModel =
MongoModel(
`basicInfo.name` = name,
`age.vatId` = age
)
}
val userUpdate = UserUpdate(name = Some("new nameeee"), age = Some("23"))
Json.toJson(userUpdate.toMongoModel) // {"basicInfo.name": "new nameeee", "age.vatId": "23"}: JsValue
Note the usage of backticks in MongoModel.