Persisting state - what to stringify | Stately | Page 1

ember coral Dec 13, 2022, 11:27 PM

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Hi, in the documentation here: https://xstate.js.org/docs/guides/states.html#persisting-state
The first line of the first code block has this code: JSON.stringify(currentState); What is current state, and how do I get it?

Thanks for your help.

States | XState Docs

Documentation for XState: State Machines and Statecharts for the Modern Web

pastel bay Dec 13, 2022, 11:35 PM

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That can come e.g. from .subscribe:

const actor = interpret(machine).start();
actor.subscribe(state => {
  const jsonState = JSON.stringify(state);

  // ...
});

ember coral Dec 14, 2022, 12:55 AM

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Thanks. This makes sense. I have a state machine that has a child state machine. I want to get the parent's state and the child's state. I was hoping the state object (as in your example) would let me access that but I don't think it does.

I think I need to research the actor model now and figure out how to update the parent with the child's state, am I on the right track?

Is there some other way to do this that I should look into?

Any help is appreciated.

pastel bay Dec 14, 2022, 1:45 AM

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I'll get back to you on this soon

pastel bay Dec 14, 2022, 2:05 PM

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So reading the ~~state~~ snapshot of a child actor is done via .getSnapshot(); e.g. if you invoked an actor with the id 'test', it would be:

// parent state
// v
state.children['test'].getSnapshot()
//                     ^
//                 child snapshot

#Persisting state - what to stringify