Feedback wanted: LaunchedEffectRetained implementation

[diousk]

I've implemented a LaunchedEffectRetained composable that aims to execute an effect only once and retain its execution across screen transitions:

@Composable
fun LaunchedEffectRetained(
    key1: Any?,
    block: suspend CoroutineScope.() -> Unit
) {
    var hasLaunched by rememberRetained(key1) { mutableStateOf(false) }
    LaunchedEffect(key1) {
        if (!hasLaunched) {
            hasLaunched = true
            block()
        }
    }
}

Usage example:

LaunchedEffectRetained(Unit) { 
    articleAPI.viewColumn(it) 
}

so that every time the navigation backstack changed and restored, the articleAPI.viewColumn(it) will be executed only once across those changes.

Behavior

• Uses rememberRetained to maintain the launched state across compositions
• Executes the block only once for a given key

Questions

• Is this the right approach for retained effects?
• Are there any edge cases or potential issues I should be aware of?
• Any suggestions for improving this implementation?

[vulpeszerda]

Looks same with https://slackhq.github.io/circuit/circuitx/#launchedimpressioneffect

[diousk]

Thanks for pointing it out!

[stagg]

As @~vulpeszerda pointed out LaunchedImpressionEffect is doing the same approach as this. Good to remember that it will only run the once, even if the suspendable is canceled early or doesn't succeed, so its best for fire and forget calls.