repeatOnLifeCycleScope

repeatOnLifeCycleScope is an extension function available for the Fragment and AppCompatActivity classes and subclasses that allows us to easily collect Flows while automatically taking care of the lifecycle changes, cancelling the Flow collection when the UI is not active and restarting it when it enters the Started state (we can customize it by giving a custom Lifecycle.State).

private fun listenStatusChanges() {
    viewModel.form.fields.value.let {
        repeatOnLifeCycleScope(
            { it[SignUpFormModel.NAME]?.status?.collect(::onNameStatusChange) },
            { it[SignUpFormModel.EMAIL]?.status?.collect(::onEmailStatusChange) },
            { it[SignUpFormModel.NEW_PASSWORD]?.status?.collect(::onPasswordStatusChange) },
            { it[SignUpFormModel.CONFIRM_PASSWORD]?.status?.collect(::onConfirmPasswordChange) },
            { viewModel.form.status.collect(::onFormStatusChange) }
        )
    }
}

Example extracted from the android example app.

In the example above we are collection various Flows with just using a single line of code per each one. For example, we are calling onNameStatusChange whenever the NAME field status changes, sending the new status received to it. And doing the same with each field status and at the end with the form’s status

It basically accepts a vararg of suspend functions where we can collect safely any type of flow, and internally it takes care of the lifecycle changes and safety measures for us.