i asked something similar a while back, but this i...

# announcements

[Ben Madore]

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"}
}

[jw]

?: run { .. }

[Ben Madore]

but <http://log.info|log.info> returns Unit, so i’d need to return a null from the run, ya?

[Ben Madore]

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

[Ben Madore]

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

[jw]

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

[Ben Madore]

where’s the fun in that 😄

[ilya.gorbunov]

also function suits such side checks well:

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