I'm migrating from `Moshi` ```@Serializable data ...

# serialization

[ursus]

I'm migrating from Moshi

@Serializable
data class User(
    val id: String,
    val name: String,
    val age: Int? = null <-----------
)

Is there a way to configure this, so I don't have to provide default value of null (just have the age be optional?
It's very error prone

[jw]

What is error prone about it? It's no less error prone than needing to specify the type or the name of each property.

[ursus]

well optionality in language is express by adding ? to the type, not ? = null

[Javier]

Why the default value should be null and not anything else?

It should be the same as setting an empty string for String. It would be doing assumptions.

[jw]

The type dictates what's allowed in the serialized form. In this case, it's an integer or a null literal.

The default indicates what value to use should the property be absent from the serialized form.

They serve different purposes.

[jw]

You can, for example, make the type non-null with a default of an integer value. That also will allow its absence in the serialized form.

[Javier]

Anyway you can config this behavior to avoid being explicit.

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

[ursus]

Hmm okay that does make sense, but not really expected coming from other parsers & ios Decodable as well

explicitNulls = false works, thanks!