Hello, could anyone help with explaining why is th...

# serialization

[kubele]

Hello, could anyone help with explaining why is this different?

@Serializable
data class Foo(
    val list: List<String> = emptyList()
)
val foo = Json.encodeToString(Foo())
println(foo)

prints

{}

but this implementation:

@Serializable
data class Foo(
    val list: List<String>
)
val foo = Json.encodeToString(Foo(emptyList()))
println(foo)

prints

{
  "list": []
}

I have no idea why it’s not

{
  "list": []
}

in both cases

[jw]

Because values matching the default value are not serialized. I believe you can disable this on the Json configuration, though.

[jw]

https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/json.md#encoding-defaults

[jw]

behavior documented at https://github.com/Kotlin/kotlinx.serialization/blob/master/docs/basic-serialization.md#defaults-are-not-encoded