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//reactivestate/com.ensody.reactivestate.android/derived

derived

[android]\ fun <T> ViewModel.derived(launcher: CoroutineLauncher = if (this is CoroutineLauncher) this else SimpleCoroutineLauncher(viewModelScope), synchronous: Boolean = true, observer: AutoRunCallback<T>): StateFlow<T>

fun <T> LifecycleOwner.derived(launcher: CoroutineLauncher = if (this is CoroutineLauncher) this else LifecycleCoroutineLauncher(this), synchronous: Boolean = true, observer: AutoRunCallback<T>): StateFlow<T>

Creates a StateFlow that computes its value based on other StateFlows via an autoRun block.

This behaves like SharingStarted.Eagerly and computes the initial value by executing the observer function immediately.

[android]\ fun <T> ViewModel.derived(initial: T, started: SharingStarted = SharingStarted.Eagerly, launcher: CoroutineLauncher = if (this is CoroutineLauncher) this else SimpleCoroutineLauncher(viewModelScope), flowTransformer: AutoRunFlowTransformer = { conflatedWorker(transform = it) }, dispatcher: CoroutineDispatcher = dispatchers.main, withLoading: MutableValueFlow<Int>? = if (this is CoroutineLauncher) launcher.loading else null, observer: CoAutoRunCallback<T>): StateFlow<T>

fun <T> LifecycleOwner.derived(initial: T, started: SharingStarted = SharingStarted.Eagerly, launcher: CoroutineLauncher = if (this is CoroutineLauncher) this else LifecycleCoroutineLauncher(this), flowTransformer: AutoRunFlowTransformer = { conflatedWorker(transform = it) }, dispatcher: CoroutineDispatcher = dispatchers.main, withLoading: MutableValueFlow<Int>? = if (this is CoroutineLauncher) launcher.loading else null, observer: CoAutoRunCallback<T>): StateFlow<T>

Creates a StateFlow that computes its value based on other StateFlows via a suspendable coAutoRun block.

You can use this to compute values on-demand only via SharingStarted.WhileSubscribed.

Parameters

android

initial The initial value (until the first computation finishes).
started When the value should be updated. Pass SharingStarted.WhileSubscribed to compute only on demand. Defaults to SharingStarted.Eagerly.
launcher The CoroutineLauncher to use.
flowTransformer How changes should be executed/collected. Defaults to conflatedWorker.
dispatcher The CoroutineDispatcher to use. Defaults to dispatchers.main.
withLoading Tracks loading state for the (re-)computation. Defaults to CoroutineLauncher.loading if this is a CoroutineLauncher or null otherwise.
observer The callback which is used to track the observables.