If you’re looking at some Jetpack Compose code or tutorials written last year, you might see the use of onCommit, onActive, and onDispose. However, these functions are no longer present in Android’s developer documentation. They were deprecated in version 1.0.0-alpha11 in favor of SideEffect and DisposableEffect. Here’s how to use those new functions and update your code.

What do they do?

Composables should be side-effect free and not handle use cases such as connecting with a HTTP API or showing a snackbar directly. You should use the side effect APIs in Jetpack Compose to ensure that these effects are run in a predictable way, rather than writing it alongside your UI rendering code.

onCommit with just a callback

This simple use case has a simple update. Just use the new SideEffect function instead.

// Before
onCommit {
  sideEffectRunEveryComposition()
}

// After
SideEffect {
  sideEffectRunEveryComposition()
}

onCommit with keys

If you only want to run your side effect when keys are changed, then you should LaunchedEffect if you don’t call onDispose. (If you do, scroll down to the next section.)

// Before
onCommit(userId) {
  searchUser(userId)
}

// After
LaunchedEffect(userId) {
  searchUser(userId)
}

onCommit with onDispose

Effects using onDispose to clean up are now handled in a separate function called DisposableEffect.

// Before
onCommit(userId) {
  val subscription = subscribeToUser(userId)

  onDispose {
    subscription.cleanup()
  }
}

// After
DisposableEffect(userId) {
  val subscription = subscribeToUser(userId)

  onDispose {
    subscription.cleanup()
  }
}

onActive

Rather than having a separate function for running an effect only on the first composition, this use cases is now handled by passing Unit as a key to LaunchedEffect or DisposableEffect. You can pass any static value as a key, including Unit or true.

// Before
onActive {
  search()
}

// After
LaunchedEffect(Unit) {
  search()
}

onActive with onDispose

// Before
onActive {
  val subscription = subscribe()

  onDispose {
    subscription.cleanup()
  }
}

// After
DisposableEffect(Unit) {
  val subscription = subscribe()

  onDispose {
    subscription.cleanup()
  }
}