i asked something similar a while back but this is slightly kotlinlang #announcements

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Title

b

Ben Madore

10/11/2019, 8:31 PM

i asked something similar a while back, but this is slightly different. is there a standard extension function that takes a block, and only executes that block if receiver is null. something like:

fun <T> T?.whenNull(block: T?.() -> Unit): T? {
    if (this == null) {
        block()
    }
    return this
}

to be used like:

return getFoo().whenNull {
  <http://log.info|log.info> {"can't find a foo"}
}

j

jw

10/11/2019, 8:31 PM

?: run { .. }

b

Ben Madore

10/11/2019, 8:35 PM

but

<http://log.info|log.info>

returns Unit, so i’d need to return a null from the run, ya?

yep, looks like it would have to be:

return getFoo() ?: run {
  <http://log.info|log.info> {"can't find a foo"}
  null
}

which isn’t particularly expressive imo

i’m fine with using my own function, just didn’t know if there was a built-in

j

jw

10/11/2019, 8:44 PM

seems like you should just assign a local and do a normal null check

b

Ben Madore

10/11/2019, 9:11 PM

where’s the fun in that 😄

i

ilya.gorbunov

10/11/2019, 10:39 PM

also

function suits such side checks well:

return getFoo().also {
    if (it == null) <http://log.info|log.info>("Can't find foo")
}

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