What are my options if I want to supply a default ...

# announcements

[Edgars]

What are my options if I want to supply a default value if an object is null when chaining calls?

[Edgars]

E.g.

(resources?.getString(R.string.foo) ?: "")
    .let { /* ... */ }

Is there any better way? Something like:

resources?.getString(R.string.foo)
    .ifNull { "" }
    .let { }

[gergo]

for strings / collections there is orEmpty()

[Edgars]

But if I want to specify a default value, then there's nothing, right?

[Joris PZ]

Couldn't you do

resource?.getString(R.string.foo)
   ?.let {

   }
   ?: "default"

[Joris PZ]

Oh wait, I see in OP's version the lambda in let would be executed on the default value, which doesn't happen in my version...

[Edgars]

Yeah. Sort of like default values for parameters in methods.

[dave08]

(resources?.getString(R.string.foo) ?: "")
    .let { }

[dave08]

inline fun <reified T: Any> T?.defaultIfNull(default: T): T = if (this == null) default else this

[agrosner]

would be nice to have something like in Swift where you only need to supply the first ? on the object. the subsequent ? are cluttery

[gildor]

I like current explicit behaviour more. Otherwise you have problems with extension function with nullable receiver
There is discussion on Kotlin Forum about this, as I remember