Xstate: onDone not triggered for parallel states

[renerbaffa]

Description
I was studying parallel states and more specifically trying out the example in the documentation (https://xstate.js.org/docs/guides/final.html#parallel-states). The onDone function does not get fired when children states get into the final state.

This issue might be related to https://github.com/davidkpiano/xstate/issues/335?

Expected Result
As the example in the documentation, onDone should be fired when the children get into the final state.

Actual Result
onDone is not fired when the children get into the final state.

Reproduction
https://codesandbox.io/s/nifty-ganguly-8bnei

Additional context
Latest version of xstate (4.8.0)

[davidkpiano]

Try doing it in a child parallel state, rather than directly on the machine.

[renerbaffa]

It works only for the first parallel child moving to a final state.
The second onDone is also not being fired:

https://codesandbox.io/s/infallible-haze-h73e2

You can change the order of events sent to see it.

In any case, if that onDone in the machine level does not work, how would you fill up data to pass context to the parent?

[renerbaffa]

what would be the direction here?

[knobo]

I have the same problem.

[knobo]

Wrapping the whole thing in as a child state worked. But it's a bug anyway.

[davidkpiano]

Looking into this now.

EDIT: This might be a trickier issue than thought. onDone gets triggered due to an event, but the problem is that since this is the root node, the machine has already terminated and stopped receiving events before the done event is sent.

Can you please tell me your use-cases @knobo @renerbaffa ? You can just use service.onDone(...).

[knobo]

My use-case was fetching all resources needed by a webpage before displaying it.
It works for me to do it as I did, by wrapping it as a child state. I don't have to have this fixed now, but it should be documented. Because it took me some time to figure this out.

[Andarist]

@davidkpiano maybe we could also add a dev-only working when we find onDone defined on the root? As it can't work (because the machine is determined by then, like you have said) then we could just surface misusage to the user early.

[renerbaffa]

My use-case is similar to @knobo. Fetching from different sources and moving on with the parent state afterwards. service.onDone(...) worked as pointed out.
I liked the idea of adding this use-case in the documentation. Would have saved me some time 😅