choosing-derivedstateof

Use derivedStateOf when the input state updates far more often than the derived output changes, such as converting firstVisibleItemIndex into a boolean. If input and output change at the same rate, it adds a snapshot subscription with no filtering benefit.

A derivedStateOf that never updates usually captures a non-state variable by its initial value inside remember { }. Pass that variable as a remember key, for example remember(threshold) { derivedStateOf { ... } }, so a new derived state is created when it changes.

Use derivedStateOf when a composable reads the derived value and should only recompose when the result changes. Use snapshotFlow inside LaunchedEffect for fire-and-forget side effects like analytics or snackbars, keeping the signal out of composition entirely.

Recomposition counts stay high when the remember wrapper is missing, when input and output frequencies match, or when another state read or wrong-phase modifier invalidates the same scope. Verify with Layout Inspector or @TraceRecomposition before and after the change.

No. Wrapping a collected flow in derivedStateOf adds a subscription layer for nothing. Filter upstream on the flow itself using distinctUntilChanged() or map { } operators instead.