Does it make a difference if, in a composable function, you declare lambda first, and pass it as an ...

# compose

[K Merle]

Does it make a difference if, in a composable function, you declare lambda first, and pass it as an argument, or directly pass it as an argument?

@Composable
fun Parent() {
    val argument = {
        // Do something
    }
    Child(param = argument)
}

fun Child(param: () -> Unit) {}

vs

@Composable
fun Parent() {
    Child(param = {
        // Do something
    })
}

fun Child(param: () -> Unit) {}

[MR3Y]

You might go with option one but you should wrap it in a remember{} when you want to memoize a non-stable variable capturing lambda, so you memoize it to avoid a lot of unnessecary recompositions Jetpack compose performane gotchas, Option 2: remembered lambdas, otherwise i would just stick with option 2

[K Merle]

But it does not make a difference I think version 1 or 2, both of these are re-declared once created?

[MR3Y]

No, there is a difference! I suggest you to take a look at this twitter thread: https://twitter.com/shikasd_/status/1555754156346015744 to see the underlying representation of lambdas on JVM and how does the compose compiler optimize those (when it knows what lambdas to optimize!)

[K Merle]

Will take a look, thank you.

[MR3Y]

Also, notice that I'm saying you should WRAP the lambda in a remember{} in order to memoize it, otherwise I believe there is no difference

[Leland Richardson [G]]

assuming the body of the lambda is the same, it should not make any difference. if you notice somewhere that it does, please file a bug