Hello, Is there any standard function with similar...

# getting-started

[Anton Lakotka [JB]]

Hello, Is there any standard function with similar behaviour (ifNull extension function)? Or maybe there are some nice idiomatic ways to do that?

-.kt

[marstran]

Just use let and ?:.

superHeavyOperation()
    ?.let { -24 + it.length } ?: 42

[Anton Lakotka [JB]]

oh yeah, that makes sense. thanks. I slightly over-engineered 🙂

[Alowaniak]

I keep saying it, but make sure that your let expression does not return null or the else wil lalso be executed

[Anton Lakotka [JB]]

yeah, that's a good point.

[marstran]

That's a feature, not a limitation if you ask me 😉

[Alowaniak]

Well feature of let sure, but if that's not desirable maybe you'll want to use also or apply
Personally I would probably go for

when(val it = superHeavyOperation()) {
  null -> 42
  else -> -24 + it.length
}

[Anton Lakotka [JB]]

hmm, is that compilable?

[Alowaniak]

afaik yes

[Anton Lakotka [JB]]

just checked that, yes that the solution I was looking for

[Anton Lakotka [JB]]

i thought it is kind of impossible to put val declaration. so now that is it much more clear and concise

[Alowaniak]

I think it is impossible to do the call declaration and treat the when as if/elseif branches, which is a pity