docs: form.fields.x.issues() can be undefined

[hyunbinseo]

Argument of type RemoteFormIssue[] | undefined is not assignable to parameter of type Iterable<unknown> | ArrayLike<unknown>.

Type undefined is not assignable to type Iterable<unknown> | ArrayLike<unknown>. ts(2345)

{#each createPost.fields.title.issues() as issue}
{/each}

{#each addId.fields.allIssues() as issue}
{/each}

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Preview: https://svelte-dev-git-preview-kit-14628-svelte.vercel.app/

[dummdidumm]

Thank you!

While this is true, I wonder - should we instead make issues() an empty array if there are no issues? In the common case you iterate over it and if it's 0 you just show nothing. The case of const valid = !!myForm.fields.issues() which would now be const valid = myForm.fields.issues().length > 0 is less common on comparison (and we could always introduce an alias like invalid() if it turns out to be very common)

[Rich-Harris]

Alternatively we could make Svelte's types match the runtime behaviour. {#each undefined as x} and {#each null as x} are both totally fine, but you get red squigglies. I'd prefer that to making issues() return a truthy value when there are no issues

[Rich-Harris]

(is that a language-tools issue? where would we change that if we wanted to?)

[dummdidumm]

Ah right, this changed in Svelte 5 but the types in language tools were not updated to reflect that. Will fix there.

[hyunbinseo]

Since RemoteFormIssue only has a message key, could the ESLint svelte/require-each-key be disabled as well?

<!-- eslint-disable-next-line svelte/require-each-key -->
{#each addId.fields.uuid.issues() as issue}
  <p>{issue.message}</p>
{/each}

It would this cause inconsistency, but disabling this rule every single time is cumbersome and unclean.

[Rich-Harris]

So don't enable it in the first place? Not sure what you're asking

[dummdidumm]

closing in favor of sveltejs/language-tools#2863