`$submitting` is reset when `form` element is removed from DOM

[Stadly]

If you submit a form and then remove the form element from the DOM, $submitting becomes false immediately. Removing a form from the DOM while still having access to $submitting can be useful for example if the form is in a dialog, and you close the dialog on submit and want to show a spinner or something while the form is submitting.

Reproduction: https://www.sveltelab.dev/1yn0a449f76vi66?files=.%2Fsrc%2Froutes%2F%2Bpage.svelte

[ciscoheat]

I understand the problem, the reason for this is I've gotten a feature request earlier for wanting the opposite case, so there must be an option to handle both cases.

[Stadly]

I think having an option for that introduces unnecessary complexity to Superforms, since it's so easy to implement in userland.

<script lang="ts">
	import { superForm } from 'sveltekit-superforms';
	const { enhance, submitting } = superForm({});

	let formEl: HTMLFormElement | null = $state(null);
	let submittingAndFormExists = $derived($submitting && formEl);
</script>

{#if submittingAndFormExists}
	<p>Submitting and form exists</p>
{/if}

<form method="POST" use:enhance bind:this={formEl}>
</form>

I guess the problem then is that, if we consider the existing behavior a feature and not a bug, we suddenly have a breaking change.

[Stadly]

Maybe the best solution is to add an option in v2 and remove it again in v3?