<@UFC7B9QPM> I submitted a feature request for all...

# announcements

[louiscad]

@thana I submitted a feature request for allowing to explicitly request use of contentEquals a while ago: https://youtrack.jetbrains.com/issue/KT-26499
You can add your vote.

[elizarov]

I always wanted to ask what’s the use-case of storing arrays in data classes? Where does it come up?

[basher]

I can't recall if `inline class`es can do this, but this kind of thing is useful in other languages when you want type-level validation:
data class NonEmptyList<T>(val values: List<T>)

then you throw in init if the list is empty.

That's the use case that comes to mind for me anyway

[Pavlo Liapota]

@basher but you are storing List, not Array 🙂

[thana]

@elizarov in my case i need to satisfy a javascript interface which requires an array here and not a list

[elizarov]

Ah, I see. Inline classes would help here when they are really supported by JS backend.

[basher]

@Pavlo Liapota fair point! Same idea though?

[Pavlo Liapota]

The issue is with arrays only.
equals() of a List compares elements and toString() shows elements, but it does not like that for arrays.

arrayOf(1) == arrayOf(1) // false
listOf(1) == listOf(1) // true

[louiscad]

@elizarov Use case is for primitive arrays and unsigned number arrays, where using List means performance hit due to autoboxing and you don't need variable size or read-only defense.

[elizarov]

Thanks. That makes sense.