Is there a way to check if something is an object ...

# announcements

[Scott Whitman]

Is there a way to check if something is an object vs. a class? For example, how could I create this if statement?

sealed class Fruit {
    class Apple(val color: String) : Fruit()
    object Orange : Fruit()
}

fun main() {
    val list = listOf(Fruit.Apple("red"), Fruit.Orange)
    for (item in list) {
        if (/* item is object? */) /* do something */
        else /* do something else */
    }
}

[Milan Hruban]

on JVM, you can do

val isObject = item::class.objectInstance != null

[Scott Whitman]

Thanks, that helps for JVM. How about JS, native? I'm hoping to use this in multiplatform.

[andylamax]

if(item is Fruit.Orange) // . . .

[Scott Whitman]

I wish it was that simple. Unfortunately this is an oversimplified version. My use case is in a multiplatform library and I am dealing with generics.

[Lammert Westerhoff]

aren’t they all objects? Fruit.Apple("red") also creates an instance

[andylamax]

I think I do not understand your use case then

[kevin.cianfarini]

the is keyword checks to see type. For sealed classes that deal with both objects and classes you can do

when (item) {
  is Apple -> ...
  Orange -> ...
}

This is because there's only ever a single instance of Orange, so the when statement uses referential equality.