lyng/docs/json_and_kotlin_serialization.md

Json support

Since 1.0.5 we start adding JSON support.

Right now we only support basic types: maps, lists, strings, numbers, booleans. It is not yet capable of serializing classes. This functionality will be added in the 1.0.6 release.

Serializae to kotlin string

// in lyng
assertEquals("{\"a\":1}", {a: 1}.toJsonString())
void
>>> void

From the kotln side, you can use Obj.toJson() and deserialization helpers:

/**
 * Decodes the current object into a deserialized form using the provided deserialization strategy.
 * It is based on [Obj.toJson] and uses existing Kotlin Json serialization, without string representation
 * (only `JsonElement` to carry information between Kotlin and Lyng serialization worlds), thus efficient.
 *
 * @param strategy The deserialization strategy that defines how the object should be decoded.
 * @param scope An optional scope used during deserialization to define the context. Defaults to a new instance of Scope.
 * @return The deserialized object of type T.
 */
suspend fun <T>Obj.decodeSerializableWith(strategy: DeserializationStrategy<T>, scope: Scope = Scope()): T =
    Json.decodeFromJsonElement(strategy,toJson(scope))

/**
 * Decodes a serializable object of type [T] using the provided decoding scope. The deserialization uses
 * [Obj.toJson] and existing Json based serialization ithout using actual string representation, thus
 * efficient.
 *
 * @param T The type of the object to be decoded. Must be a reified type.
 * @param scope The scope used during decoding. Defaults to a new instance of [Scope].
 */
suspend inline fun <reified T>Obj.decodeSerializable(scope: Scope= Scope()) =
    decodeSerializableWith<T>(serializer<T>(), scope)

Note that lyng-2-kotlin deserialization with kotlinx.serialization is working based on JsonElement as information carrier, without formatting and parsing actual Json strings. This is why we use Json.decodeFromJsonElement instead of Json.decodeFromString. Such approach gives satisfactory performance without writing and supporting custom kotlinx.serialization codecs.