Update atom state in reaction

[c01nd01r]

Hi!
I've come across a situation where it's necessary to change the state of an atom within a reaction.

type AsyncResource = {
  hasError: Signal<boolean>;
  error: Signal<string>;
}

type NotifyStore = {
  messages: Signal<string[]>
  addMessage: (message) => void
}

const notify: NotifyStore = useNotify();
const asyncResource: AsyncResource = useAsyncResource(() => fetch('/error-response'));

useEffect(() => react('add message', () => {
  if (asyncResource.hasError.value) { 
    notify.addMessage(asyncResource.error.value)
  }
}), [])

When a reaction is triggered, the notify.messages atom gets updated, and execution fails with the error 'cannot change atoms during reaction cycle'.
From what I understand, this behavior corresponds to this test:

signia/packages/signia/src/__tests__/reactor.test.ts

Lines 20 to 30 in 1d57d3e

	it('can not set atom values directly yet', () => {
	const a = atom('', 1)
	const r = reactor('', () => {
	if (a.value < +Infinity) {
	a.update((a) => a + 1)
	}
	})
	expect(() => r.start()).toThrowErrorMatchingInlineSnapshot(
	`"cannot change atoms during reaction cycle"`
	)
	})

Are there any workarounds for this situation?

[muhajirdev]

I was having a similar issue. Finally ended up just not using signia for this one particular case.