resultOf

Observes the result of type T returned by a child screen via backWithResult.

The result is consumed exactly once: the returned State transitions from null to the received value and stays at that value until the composable leaves the composition.

Implementation notes:

• Uses KClass.simpleName as the map key — available on all KMP targets (Android, iOS, Desktop, JS, WASM). KClass.qualifiedName is not supported in Kotlin/JS.

• The results map is a androidx.compose.runtime.snapshots.SnapshotStateMap, so reading it inside derivedStateOf creates a reactive dependency — recomposition triggers automatically the moment backWithResult puts a matching entry.

• SideEffect runs synchronously after every successful recomposition. When a pending value is observed it is removed from results and committed to the stable local State in the same frame — eliminating the one-frame null window that a LaunchedEffect would introduce.

Prefer the inline reified overload resultOf when the type is known at the call site:

val result by navController.resultOf<ProfileScreen.Result>()

Parameters

Inline reified convenience overload of resultOf.

Observes the result of type T posted by a child screen via backWithResult. The result is consumed exactly once — see resultOf for full semantics.

Pattern for io.github.alimsrepo.navease.runtime.screen.ActivityScreen

Define the result as a nested data class inside the child screen, then observe it in the parent screen using this function:

// ── Child screen — posts a result before popping ─────────────────────────
class ProfileScreen : ActivityScreen<AppScreens.Profile>() {

    data class Result(val selectedUserId: Int)

    @Composable
    override fun Content(navKey: AppScreens.Profile, navController: NavController) {
        Button(onClick = {
            navController.backWithResult(Result(selectedUserId = 42))
        }) { Text("Select") }
    }
}

// ── Parent screen — observes the result ──────────────────────────────────
class HomeScreen : ActivityScreen<AppScreens.Home>() {
    @Composable
    override fun Content(navKey: AppScreens.Home, navController: NavController) {

        val result by navController.resultOf<ProfileScreen.Result>()

        result?.let { Text("Selected user #${it.selectedUserId}") }

        Button(onClick = { navController.navigate(AppScreens.Profile) }) {
            Text("Open Profile")
        }
    }
}

Type Parameters