Sending back events from a promise actor

[Ghirigoro]

Sending back from a callback actor is really straightforward - a nicely typed sendBack function is provided for you by XState and you're good to go. It's not clear to me exactly what the process is for sending back with a promise actor. As far as I can tell the way you would do this is by getting the parent and then calling send on it. For example:

const parent = system.get(parentId);
if (parent === undefined) throw new Error("Parent machine not found");
// parent is `any` so we have to cast
parent.send({ type: "response", response: null } as MyEventType);

Managing ids and a loss of typesafety doesn't seem right for such a basic task, especially since similar tasks have a clean API for it. What am I missing? Looking at the docs the only thing I see is a mention about passing in a reference to the parent using the input, but its not clear to me how one would do that.

Any help would be appreciated. Thanks

[davidkpiano]

Looking at the docs the only thing I see is a mention about passing in a reference to the parent using the input, but its not clear to me how one would do that.

This is how you would do that:

const someMachine = createMachine({
  // ...
  invoke: {
    src: promiseLogic,
    input: ({ self }) => ({ parent: self })
  }
});


const promiseLogic = fromPromise(({ input }: {
  input: { parent: ActorRefFrom<typeof someLogic> }
}) => {
  // ...
  input.parent.send({/* ... */}); // Should be strongly-typed
  // ...
})