subscribe to state changes even if always next state?

[jediforri]

If I have a machine state like

  //       [STATE_OUTSIDE_UP]: {
  //         entry: ENTRY_UP,
  //         always: STATE_OUTSIDE
  //       },

and I subscribe to state changes like so:

    const subscription = rDragActor.subscribe( state => {
      // Called whenever the state changes

I do not get updates from the 'pass-through' state that has an always transition.

Is there a configuration flag I can get to ensure these 'pass-through' states are part of my subscription?

I know I can fire events, but this leads to a separation of concerns for how I handle states in my component.

Feels like an anti-pattern.

Thanks for your help.

[DahanItamar]

There is no actor.subscribe option that emits the intermediate state of an always transition. In v5, subscribers receive the settled snapshot after the event and its eventless transitions have been processed.

For observing those intermediate states, use the inspection API's microstep events:

import { createActor, createMachine } from 'xstate';

const machine = createMachine({
  initial: 'outside',
  states: {
    outside: { on: { UP: 'outsideUp' } },
    outsideUp: { always: 'outside' },
  },
});

const actor = createActor(machine, {
  inspect(event) {
    if (event.type === '@xstate.microstep') {
      console.log(event.snapshot.value);
    }
  },
});

actor.start();
actor.send({ type: 'UP' });

This observes outsideUp and then outside. A regular snapshot subscription sees the settled outside state; the transient state's entry actions still execute.

Inspection is useful for tracing and debugging. If your component needs outsideUp to remain an observable UI state, leave it only after a subsequent event instead of an immediate always transition.

Tested with XState 5.33.2. The v5 microstep event includes the intermediate snapshot.