Modify json field type via circe

Question

I have simple Json:

val str = """{"test":"123"}"""

How I can modify String "123" to Int 123 to get new Json?:

{"test":123}

Now I am using:

val json = parse(str).getOrElse(Json.Null)
val jsObj = json.asObject.get  // Unsafe, just example
val newJson = Json.fromJsonObject(jsObj.remove("test").add("test", Json.fromInt(123)))

But this code is not pretty.

Is it possible to make this code prettier or maybe do it via circe optics?

You probably don't need `remove` though. – slouc Apr 29 '19 at 12:37 — slouc, Apr 29 '19 at 12:37

score 4 · Accepted Answer · answered Apr 29 '19 at 12:57

4

It should do the trick depending on how you want to manage the limit case (here I throw an exception):

import io.circe._
import io.circe.parser.parse

val str = """{"test":"123"}"""
val json = parse(str).getOrElse(Json.Null)
json.mapObject(
  _.mapValues( v =>
    v.asString
     .flatMap(parse(_).toOption)
     .getOrElse(throw new IllegalArgumentException("No String found"))
  )
)

answered Apr 29 '19 at 12:57

Benjamin Vialatou

626
5
8

3

This does not compile, but I fix it. Thanks for the idea. `json.mapObject( _.add("test",Json.fromInt(321)))` – Oleg Apr 29 '19 at 13:24

Modify json field type via circe

1 Answers1