Convert a dataclass into another (very similar) dataclass. This can be useful for usecases like you would use unpack in Python, or to make simple changes to an existing object for backwards compatibility. Uses https://kotlinlang.org/docs/reflection.html

unpack_data_classes.kt

// Heavly based on this post. All credits to the author.
// https://www.bezkoder.com/kotlin-convert-object-data-class-to-another/

// build.gradle.kt
implementation("org.jetbrains.kotlin:kotlin-reflect:1.6.0")

// file.kt
import kotlin.reflect.full.memberProperties

data class Customer(
  val firstName: String,
  val lastName: String,
  val phone: String,
  val age: Int,
  val location: String
)

data class CustomerRecord(
  val fullName: String,
  val phone: String,
  val age: Int,
  val location: String
)

fun Customer.toRecord() = with(::CustomerRecord) {
    val propertiesByName = Customer::class.memberProperties.associateBy { it.name }

    callBy(
        args = parameters.associateWith { parameter ->
            when (parameter.name) {
                "fullName" -> "$firstName $lastName",
                // any fields that are different come here
                else -> propertiesByName[parameter.name]?.get(this@toRecord)
            }
        }
    )
}