fromObservable

Callable

• fromObservable<TContext, TInput>(observableCreator: (__namedParameters: { input: TInput; self: ActorRef<ObservableSnapshot<TContext, any>, { type: string }>; system: AnyActorSystem }) => Subscribable<TContext>): ObservableActorLogic<TContext, TInput>

---

• Observable actor logic is described by an observable stream of values. Actors created from observable logic (“observable actors”) can:

  • Emit snapshots of the observable’s emitted value

  The observable’s emitted value is used as its observable actor’s context.

  Sending events to observable actors will have no effect.

  @example

  import { fromObservable, createActor } from 'xstate'
  import { interval } from 'rxjs';
  
  const logic = fromObservable((obj) => interval(1000));
  
  const actor = createActor(logic);
  
  actor.subscribe((snapshot) => {
    console.log(snapshot.context);
  });
  
  actor.start();
  // At every second:
  // Logs 0
  // Logs 1
  // Logs 2
  // ...

  @see

  • https://rxjs.dev for documentation on RxJS Observable and observable creators.
  • Subscribable interface in XState, which is based on and compatible with RxJS Observable.

  ---

  Type parameters

  • TContext
  • TInput: NonReducibleUnknown

  Parameters

  • observableCreator: (__namedParameters: { input: TInput; self: ActorRef<ObservableSnapshot<TContext, any>, { type: string }>; system: AnyActorSystem }) => Subscribable<TContext>

    A function that creates an observable. It receives one argument, an object with the following properties:

    • input - Data that was provided to the observable actor
    • self - The parent actor
    • system - The actor system to which the observable actor belongs

    It should return a Subscribable, which is compatible with an RxJS Observable, although RxJS is not required to create them.

  Returns ObservableActorLogic<TContext, TInput>