with the introduction of a lot of `orNull` functions in mind, I was unpleasantly surprised there is ...

# stdlib

[Michael de Kaste]

with the introduction of a lot of orNull functions in mind, I was unpleasantly surprised there is no such thing as List<T>.indexOfFirstOrNull

[Sam]

Looks like it’s in YouTrack but was closed on the basis that null isn’t really much more useful than -1. Personally, I’m with you; I would much prefer null. An unexpected -1 can easily go unnoticed, leading to errors down the line. Whereas the type system forces you to handle null, so if there’s a chance my index won’t exist, I definitely want that. I suppose the downside of using null is that the return type would have to be boxed. But since we’re only dealing with a single value here, I don’t see that being a big concern.

[Michael de Kaste]

how is 'null' not more usefull than''-1' 😛?

[Michael de Kaste]

but yeah I agree, it actually almost went past code review until someone notified me that I didn't catch the 'defaultValue'

[Michael de Kaste]

its definitely not typesafe to use just indexOfFirst

[Derek Peirce]

If the issue was just boxing, I'd instead like to see a value class wrapping around Int where you'd either clearly assert that you're getting a useful integer or have to write a case for when the item is not found, maybe value class Index(private val i: Int).

[mcpiroman]

you can write it as list.indexOfFirst(foo).takeUnless { it == -1 }