fix(core): improve error handling with multiple errors in flashCallbacks

[nightohl]

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Fixes #

Summary

Previously, only the first error was thrown and subsequent errors were ignored. Now all errors are collected and:

• If there's only one error, throw it directly
• If there are multiple errors, throw them as AggregateError

This change improves debugging by preserving all error information during callback execution.

Check List

• pnpm run fix for formatting and linting code and docs

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jotai	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Mar 10, 2025 0:30am

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[dai-shi]

@dmaskasky What do you think?

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commit: d873d87

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Latest commit: d873d87
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[dai-shi]

I would even go with this. Not sure about the drawback, but it's predictable.

Suggested change

	if (errors.length === 1) {
	throw errors[0]
	} else if (errors.length > 1) {
	throw new AggregateError(
	errors,
	'Multiple errors occurred during flushCallbacks',
	)
	if (errors.length) {
	throw new AggregateError(errors)

[nightohl]

@dai-shi I think it's good way to go!
I'd change commit with it and force-push, thanks!

• done

[dmaskasky]

@dmaskasky What do you think?

My main concern is that AggregateError will not pass an instance check.

try {
  store.set(someAtom, ...values)
} catch(e) {
  if (e extends FooError) {
    // handle error
  }
}

Are there examples where AggregateError is used in other open source libraries?

[dmaskasky]

Reading more on AggregateError, I think this makes sense.

Could we do

if (errors.length === 1) {
  throw errors[0]
} else if (errors.length) {
  throw new AggregateError(errors) 
}

[dai-shi]

My main concern is that AggregateError will not pass an instance check.

I don't think it's solved anyways, because you don't know if other subscribers throw an error.

[dai-shi]

I like this all-or-nothing approach. It's more predictable.

[dmaskasky]

I don't think it's solved anyways, because you don't know if other subscribers throw an error.

Should we wrap all errors in AggregateError? Is this something we should teach?

[dai-shi]

Should we wrap all errors in AggregateError? Is this something we should teach?

Yes, that's exactly my suggestion. It's harder to tell when it's wrapped otherwise.