Svelte 5 support / migration

[techniq]

Creating an overarching issue to track migrating to Svelte 5.

The plan is for LayerChart 1.x to support Svelte 3, 4, and 5 by not leveraging Svelte 5 specific features like runes and snippets, and 2.x+ will leverage these Svelte 5 specific features.

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Outstanding Svelte 5 issues:

• Svelte 5: SVG elements within fallback not displayed
  • fix: reevaluate namespace in slots sveltejs/svelte#11849

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Issues that should be investigated:

• Canvas infinite loop issue (Svelte 3/4) #158
• Console warnings on client showing div with zero negative height #291
• Cleanup non-passive event listener warnings #292

[oneezy]

any headway on 2.x ? i noticed that the latest version uses svelte 5 but didnt' see a next version using runes yet

[techniq]

@oneezy The docs are using Svelte 5, but I haven't started migrating to runes/snippets just yet. Just got back from a family vacation and transitioning jobs this/next week, but plan to start the migration in a couple of weeks. I've got my eye on the Migration Magician SvelteHack category and we'll see if I can make the Jan 9th deadline. I'm migrating Svelte UX as well...

One thing I need to figure out is @mhkeller's Svelte 5 roadmap for LayerCake. I've been contemplating removing LayerCake as a dependency (at least initially) which would simplify some context and possibly open up additional improvements.

Stay tuned, but should see some progress soon. I need to drop a 1.x release for both projects first as this will continue to be Svelte 3-5 compatible, and 2.x+ will be Svelte 5 only (since it will leverage runes, snippets, etc).

[ccalobeto]

Waiting with anxiety about the svelte 5 migration.

[vijay8i]

Hi! 👋

My project uses Svelte 5 in strict runes mode and trying to use layerchart results in the following error:

 'Cannot use `export let` in runes mode — use `$props()` instead'

FWIW, I am including this patch that let's me get past the error; and I think might benefit others if you could apply it in an interim release before reaching native Svelte 5 support which I can see is not an insignificant amount of work. Please disregard if this is not worth your time.

I am attaching the patch file in case it makes it easier to make that release.

PS: I have submitted a similar patch to layercake as well.
layerchart+0.60.3.patch

[techniq]

Hey @vijay8i. That's interesting. I see the patch is adding...

<svelte:options runes={false} />

to all the components. As long as setting this option doesn't have any Svelte 3/4 compat issues (complains the option doesn't exist, etc), I'm fine with adding it as a temporary solution to improve Svelte 5 compat. If you could validate the change works with Svelte 4 and submit a PR, I'll happily merge it.

I haven't been as active on LayerChart development in December due to changing jobs and holidays with family (and a few other items), but plan to start the Svelte 5 migration (as next branch / releases) very soon. I'm wrapping some outstanding PRs and will be making a 1.0 release which will retain Svelte 3-5 compatibility and then start the Svelte 5 rune/snippet/etc migration, along with a few bigger changes.

I'm currently working on overhauling how Canvas integration works which will make it much more robust and simplier. The initial work has started in [PR ](#295), but the bigger change I hope to start this week. It's the biggest blocker for Svelte 5 migration work.

[vijay8i]

Hi @techniq,

I'm fine with adding it as a temporary solution to improve Svelte 5 compat. If you could validate the change works with Svelte 4 and submit a PR, I'll happily merge it.

I don't think this patch will work with Svelte 4 or below. This option was introduced in Svelte 5, so pretty iffy to even try on anything lower. The intent of my comment was to hope that you could add this to next branch that is meant to move to runes while still working on it.

I haven't been as active on LayerChart development in December due to changing jobs and holidays with family (and a few other items), but plan to start the Svelte 5 migration (as next branch / releases) very soon.

I understand. Fwiw, you are way ahead than most of us in our aspirations to build and maintain an open source library that offers utility and is used widely. More power to you.