```fun <T> List<Int>.transform( block: (Int) -> T = { it } ): List<T> { ...

# getting-started

[jeggy]

fun <T> List<Int>.transform(
    block: (Int) -> T = { it }
): List<T> {
    return map { block(it) }
}

fun main() {
    val items = listOf(1, 2, 3)
    
    println(items.transform { "$it, " })
    println(items.transform())
}

Does anyone know if there is a issue on youtrack somewhere discussing making something like this possible?

[August Lilleaas]

what’s the expected output of those printlns?

[Sam]

So the issue is that the default value for the block parameter implies a default value for T?

[jeggy]

exactly, but this is not possible with kotlin currently

[Sam]

I would just do it with old-fashioned overloads:

fun List<Int>.transform(): List<Int> = transform { it }
fun <T> List<Int>.transform(block: (Int) -> T): List<T> = map { block(it) }

[jeggy]

Nice and simple solution 🙂
Thanks

[jeggy]

but would still be nice to have support for it as a single function

[ephemient]

https://youtrack.jetbrains.com/issue/KT-52519/Allow-the-default-argument-in-a-function-to-dictate-the-type-if-no-argument-is-supplied