Source.UnfoldAsync(TState, TElem) Method

SourceUnfoldAsyncTState, TElem Method

Same as UnfoldTState, TElem(TState, FuncTState, TupleTState, TElem), but uses an async function to generate the next state-element tuple.

Namespace: Akka.Streams.Dsl
Assembly: Akka.Streams (in Akka.Streams.dll) Version: 1.2.3.129 (1.2.3.129)

Syntax

Copy

public static Source<TElem, NotUsed> UnfoldAsync<TState, TElem>(
	TState state,
	Func<TState, Task<Tuple<TState, TElem>>> unfoldAsync
)

static member UnfoldAsync : 
        state : 'TState * 
        unfoldAsync : Func<'TState, Task<Tuple<'TState, 'TElem>>> -> Source<'TElem, NotUsed>

Parameters

state: Type: TState
TBD
unfoldAsync: Type: SystemFuncTState, TaskTupleTState, TElem
TBD

Type Parameters

TState: TBD
TElem: TBD

Return Value

Type: SourceTElem, NotUsed
TBD

Examples

For example, all the Fibonacci numbers under 10M:

Copy

Source.unfoldAsync(0 → 1) {
 case (a, _) if a > 10000000 ⇒ Future.successful(None)
 case (a, b) ⇒ Future{
   Thread.sleep(1000)
   Some((b → (a + b)) → a)
 }
}

Reference

Source Class

Akka.Streams.Dsl Namespace