What is the diffrence between JsObject and JsValue in Scala?

Question

JsObject and JsValue solves almost the same purpose but in JsObject

val data[JsObject] = Json.obj("id1"-> "some_id1")
val newData[JsObject] = data ++ Json.obj("id"-> "some_id")

we can add a new key-value pair in JsObject but I still haven't figure out how to add a key-value pair in JsValue

Answer 1

You can do more with JsObject because it is a subclass of JsValue that represents a JSON object ({...}). JsValue can be a string, numeric, object or array. Therefore you can't assume that it has key value pairs. If you have a val x: JsValue that you know is a JsObject you can use x.as[JsObject] to cast it or if you're not sure it's a JsObject you can use x.asOpt[JsObject] to get an Option[JsObject].