TypeScript 6 compatibility

[rgieseke]

SvelteKit supports TypeScript 6 so I think it might be possible to remove the peer dependency for "typescript": "^5.0.2" in Layer Cake.

There are a bunch of changes in the Kit PR which haven't yet dug into (changes to config options, e.g. strict is removed, and some type declarations are removed, like /** @type {import('./$types').PageServerLoad} */):

sveltejs/kit#15595

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[rgieseke]

On main and in this PR I get the same number of errors with npm run check:

svelte-check found 463 errors and 19 warnings in 108 files

[mhkeller]

Thanks for starting this. What do you think the failing playwright test is about?

[Copilot]

Pull request overview

Updates the project’s SvelteKit toolchain to support TypeScript 6 and removes the package-level TypeScript peer dependency.

Changes:

• Bump SvelteKit and related Svelte tooling versions and update TypeScript to ^6.0.2.
• Remove typescript from peerDependencies, leaving svelte as the only peer dependency.
• Regenerate package-lock.json to reflect the dependency upgrades.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
package.json	Upgrades Svelte/SvelteKit/TypeScript dev deps and removes the TypeScript peer dependency.
package-lock.json	Updates the resolved dependency graph for the upgraded Svelte/SvelteKit/TypeScript toolchain.

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[Copilot]

engines.node currently allows Node ^20.17.0 || >=22.9.0, but the updated toolchain in this PR pulls in Vite 7.x which requires Node ^20.19.0 || >=22.12.0 (per package-lock.json). This mismatch can cause installs to fail under engine-strict setups or mislead users about supported Node versions. Consider bumping the engine range to match the strictest dependency requirement (or pinning Vite/@sveltejs/vite-plugin-svelte to versions compatible with the current engine range).

[rgieseke]

Sveltekit has

"engines": {
	"node": ">=18.13"
}

Maybe we don't need to pin node anymore in Layer Cake?

[rgieseke]

Thanks for starting this. What do you think the failing playwright test is about?

Looks like some node actions being outdated issues maybe?

https://github.com/mhkeller/layercake/actions/runs/24331283820/job/71037519592

I'll try and see if an update fixes it.

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[rgieseke]

Ok, seems to have been an issue with npm changing something about promise-retry:

I tried a workaround with pinning to a sub-version from:

npm/cli#9151

There was a fix here with more details on the issue:

npm/cli#9152

Do you remember why we needed an update to 11, @mhkeller?

[rgieseke]

Do you remember why we needed an update to 11, @mhkeller?

I removed the npm install and it seems to also run with the default npm 10.9.7 included in the image.