Put Data in mutlple branch of Array : Json Transformer ,Scala Play - json

Question

i want to add values to all the arrays in json object.
For eg:
value array [4,2.5,2.5,1.5]
json =
{
"items": [
{
"id": 1,
"name": "one",
"price": {}
},
{
"id": 2,
"name": "two"
},
{
"id": 3,
"name": "three",
"price": {}
},
{
"id": 4,
"name": "four",
"price": {
"value": 1.5
}
}
]
}
i want to transform the above json in
{
"items": [
{
"id": 1,
"name": "one",
"price": {
"value": 4
}
},
{
"id": 2,
"name": "two",
"price": {
"value": 2.5
}
},
{
"id": 3,
"name": "three",
"price": {
"value": 2.5
}
},
{
"id": 4,
"name": "four",
"price": {
"value": 1.5
}
}
]
}
Any suggestions on how do i achieve this. My goal is to put values inside the specific fields of json array. I am using play json library throughout my application. What other options do i have instead of using json transformers.

Answer 1

You may use simple transformation like
val prices = List[Double](4,2.5,2.5,1.5).map(price => Json.obj("price" -> Json.obj("value" -> price)))
val t = (__ \ "items").json.update(
of[List[JsObject]]
.map(_.zip(prices).map(o => _._1 ++ _._2))
.map(JsArray)
)
res5: play.api.libs.json.JsResult[play.api.libs.json.JsObject] = JsSuccess({"items":[{"id":1,"name":"one","price":{"value":4}},{"id":2,"name":"two","price":{"value":2.5}},{"id":3,"name":"three","price":{"value":2.5}},{"id":4,"name":"four","price":{"value":1.5}}]},/items)

Answer 2

I suggest using classes, but not sure this fits to your project because it's hard to guess how your whole codes look like.
I put new Item manually for simplicity. You can create items using Json library :)
class Price(val value:Double) {
override def toString = s"{value:${value}}"
}
class Item(val id: Int, val name: String, val price: Price) {
def this(id: Int, name: String) {
this(id, name, null)
}
override def toString = s"{id:${id}, name:${name}, price:${price}}"
}
val price = Array(4, 2.5, 2.5, 1.5)
/** You might convert Json data to List[Item] using Json library instead. */
val items: List[Item] = List(
new Item(1, "one"),
new Item(2, "two"),
new Item(3, "three"),
new Item(4, "four", new Price(1.5))
)
val valueMappedItems = items.zipWithIndex.map{case (item, index) =>
if (item.price == null) {
new Item(item.id, item.name, new Price(price(index)))
} else {
item
}
}