Hi! Did anyone had issue serializing `Map<Strin...

# javascript

[Császár Ákos]

Hi!
Did anyone had issue serializing Map<String, MyClass>?
I have the following class which contains a Map<String, Meta>

@JsExport
@ExperimentalJsExport
@Serializable
data class TvChannel internal constructor(
    @SerialName("metas")
    private val metas: Map<String, Meta>? = null,
)

The Meta interface has a polymorphic serializer.

@OptIn(ExperimentalJsExport::class)
@Serializable(with = MetaSerializer::class)
interface Meta {
  val objectType : String?
}

In Js I get the following error for this code:

val myTvChannel = TvChannel()
console.log(myTvChannel)

TypeError: Converting circular structure to JSON
--> starting at object with constructor 'LinkedHashMap'
| property 'ab_1' -> object with constructor 'ChainEntry'
--- property 'ib_1' closes the circle
at JSON.stringify (<anonymous>)
at Inspector.ts:129:1
at Array.forEach (<anonymous>)
at Inspector.addMessageToLogsContainer (Inspector.ts:127:1)
at console.log (Inspector.ts:38:1)

With Map<String, String> it works, but I don't understand why it is not working with Map<String, MyClass>.

[Artem Kobzar]

Hey, what version of the compiler do you have?

[Császár Ákos]

1.8.22

[Artem Kobzar]

Could you check if the exact code works with the 1.9.10?

[Császár Ákos]

I get the same error with 1.9.10

[ian.shaun.thomas]

it's because of the structure of maps, are you sure you're using the kotlin serialization json and not accidentally using the js json?

[Császár Ákos]

In my case, I have a KMP library which is exported as an npm package, and it is imported to a js project.
The library returns the mentioned TvChannel class to the client app.
The client app uses console.log() (which is, based on the stacktrace, uses the js json, JSON.stringify() ) on the TvChannel instance.
Correct me if I'm wrong but in this case I think its unavoidable for the client app, to use js json.

[ian.shaun.thomas]

I have a client app and I use js json and kotlin serialization json where necessary.