What is preferred: `lateinit var` or assigning the value to a `val` that way it’s not mutable? Exam...

# announcements

[Nick]

What is preferred: lateinit var or assigning the value to a val that way it’s not mutable?

Example lateinit var:

late init var foo: Bar()

fun goTime() {
   foo = Bar()
   println(foo)
}

Example var:

var foo: Bar? = null

fun goTime() {
   val foo = foo ?: Bar()
   println(foo)
}

[Sourabh Rawat]

Both has different usecase.
I tend to use val more unless I need mutablity.
The only place I would use lateinit var when I don't need mutability is when I can't provide it's initial value at the time of declaration. E.g.- field dependency injection, Android classes

[ephemient]

not a great example as lateinit primitive doesn't work… https://youtrack.jetbrains.com/issue/KT-15284

[ephemient]

if it must be deferred, I would use something like

val foo: Int by lazy {
    1
}

where possible

[Sourabh Rawat]

For primitives, instead of lateinit, Delegates.notNull is used.

[Nick]

ahh, yeah that was just an example. I’ll update it so it’s an object.