Optional inputs in v5

[AnatoleLucet]

I'm trying to create a state machines which takes optional inputs, but I cannot figure out how to do this using the input() function.

const test = setup({
  types: {} as {
    input?: {
      foo?: string;
    };
  },
}).createMachine({
  context: ({ input = {} }) => ({
    foo: input.foo ?? "bar",
  }),
});

createActor(test); // error missing "input" property
createActor(test, { input: undefined }); // no error but not very practical

[Andarist]

This one works with exactOptionalPropertyTypes (not that I recommend you enable this setting right now):

// @exactOptionalPropertyTypes: true
import { setup, createActor } from "xstate"; // types: 5.9.1

const test = setup({
  types: {} as {
    input:
      | {
          foo?: string;
        }
      | undefined;
  },
}).createMachine({
  context: ({ input = {} }) => ({
    foo: input.foo ?? "bar",
  }),
});

createActor(test);
createActor(test, { input: undefined });
createActor(test, { input: { foo: "" } });

TS playground

Inference from optional properties is a little bit weird in this sense. I'll have to think more about potential solutions for this on our side.

[AnatoleLucet]

Great! Seems to work fine when using createActor, but I get a new error when using it with spawnChild inside of a machine's entry: ....

Repro

Is this a mistake from my end?