feat: TypeScript 6.0 by teemingc · Pull Request #15595 · sveltejs/kit

teemingc · 2026-03-24T08:56:20Z

This PR extends the SvelteKit peerDep range to include TS 6.0. It also upgrades our apps/packages using TS purely as a devDependency to use 6.0 (this excludes kit because we use TS to generate public types and that can be a breaking change. package is also excluded because it can't support TS6 until svelte2tsx does).

TODOs

update svelte-check fix: typescript 6.0 compatibility language-tools#2988~

Required for @sveltejs/package if we want to support TS6 in the future:

update svelte2tsx feat: typescript 6.0 support language-tools#2985
update svelte-preprocess feat: support TypeScript 6 svelte-preprocess#675

Required for SvelteKit 3 when we switch over to TS6 completely

update @sveltejs/eslint-config chore: upgrade to typescript 6 eslint-config#67
update dts-buddy feat: TypeScript 6.0 dts-buddy#123

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changeset-bot · 2026-03-24T08:56:26Z

🦋 Changeset detected

Latest commit: b5062d1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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@sveltejs/kit	Minor

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jasonlyu123 · 2026-03-24T09:46:56Z

but I can't find this reference in this repo nor language-tools. Where is this coming from?

This is fixed in sveltejs/language-tools#2985. It's a problem with a version check that doesn't consider the major version number 😅. I think I could extract this one out into a separate PR.

teemingc · 2026-03-27T17:41:29Z

but I can't find this reference in this repo nor language-tools. Where is this coming from?

This is fixed in sveltejs/language-tools#2985. It's a problem with a version check that doesn't consider the major version number 😅. I think I could extract this one out into a separate PR.

I've updated svelte-check to get the fix from sveltejs/language-tools#2988 but the same error message still occurs. Do we need to wait for the full TS6 compatibility PR?

jasonlyu123 · 2026-03-31T01:20:24Z

I just released the fix from sveltejs/language-tools#2988. Could you try it again now?

teemingc · 2026-03-31T08:34:20Z

I just released the fix from sveltejs/language-tools#2988. Could you try it again now?

Thank you! It works

svelte-docs-bot · 2026-03-31T17:35:08Z

Preview: https://svelte-dev-git-preview-kit-15595-svelte.vercel.app/

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @sveltejs/kit@2.56.0 ### Minor Changes - breaking: rework client-driven refreshes ([#15562](#15562)) - breaking: stabilize remote function caching by sorting object keys ([#15570](#15570)) - breaking: add `run()` method to queries, disallow awaiting queries outside render ([#15533](#15533)) - feat: support TypeScript 6.0 ([#15595](#15595)) - breaking: isolate command-triggered query refresh failures per-query ([#15562](#15562)) - feat: use `hydratable` for remote function transport ([#15533](#15533)) - feat: allow `form` fields to specify a default value (`field.as(type, value)`) ([#15577](#15577)) ### Patch Changes - fix: don't request new data when `.refresh` is called on a query with no cache entry ([#15533](#15533)) - fix: allow using multiple remote functions within one async derived ([#15561](#15561)) - fix: avoid false-positive overridden Vite `base` setting warning when setting a `paths.base` in `svelte.config.js` ([#15623](#15623)) - fix: manage queries in their own `$effect.root` ([#15533](#15533)) - fix: avoid `inlineDynamicImports` deprecation warning when building the service worker with Vite 8 ([#15550](#15550)) - fix: correctly escape backticks when precomputing CSS ([#15593](#15593)) - fix: discard obsolete forks before finishing navigation ([#15634](#15634)) - chore: tighten up override implementation ([#15562](#15562)) - fix: ensure the default Svelte 5 `error.svelte` file uses runes mode ([#15609](#15609)) - fix: deduplicate same-cache-key `batch` calls during SSR ([#15533](#15533)) - fix: decrement pending_count when form callback doesn't call submit() ([#15520](#15520)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [@sveltejs/kit](https://svelte.dev) ([source](https://github.com/sveltejs/kit/tree/HEAD/packages/kit)) | [`2.55.0` → `2.56.1`](https://renovatebot.com/diffs/npm/@sveltejs%2fkit/2.55.0/2.56.1) | ![age](https://developer.mend.io/api/mc/badges/age/npm/@sveltejs%2fkit/2.56.1?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/@sveltejs%2fkit/2.55.0/2.56.1?slim=true) | --- ### Release Notes <details> <summary>sveltejs/kit (@sveltejs/kit)</summary> ### [`v2.56.1`](https://github.com/sveltejs/kit/blob/HEAD/packages/kit/CHANGELOG.md#2561) [Compare Source](https://github.com/sveltejs/kit/compare/@sveltejs/kit@2.56.0...@sveltejs/kit@2.56.1) ##### Patch Changes - chore: update JSDoc ([#15640](sveltejs/kit#15640)) ### [`v2.56.0`](https://github.com/sveltejs/kit/blob/HEAD/packages/kit/CHANGELOG.md#2560) [Compare Source](https://github.com/sveltejs/kit/compare/@sveltejs/kit@2.55.0...@sveltejs/kit@2.56.0) ##### Minor Changes - breaking: rework client-driven refreshes ([#15562](sveltejs/kit#15562)) - breaking: stabilize remote function caching by sorting object keys ([#15570](sveltejs/kit#15570)) - breaking: add `run()` method to queries, disallow awaiting queries outside render ([#15533](sveltejs/kit#15533)) - feat: support TypeScript 6.0 ([#15595](sveltejs/kit#15595)) - breaking: isolate command-triggered query refresh failures per-query ([#15562](sveltejs/kit#15562)) - feat: use `hydratable` for remote function transport ([#15533](sveltejs/kit#15533)) - feat: allow `form` fields to specify a default value (`field.as(type, value)`) ([#15577](sveltejs/kit#15577)) ##### Patch Changes - fix: don't request new data when `.refresh` is called on a query with no cache entry ([#15533](sveltejs/kit#15533)) - fix: allow using multiple remote functions within one async derived ([#15561](sveltejs/kit#15561)) - fix: avoid false-positive overridden Vite `base` setting warning when setting a `paths.base` in `svelte.config.js` ([#15623](sveltejs/kit#15623)) - fix: manage queries in their own `$effect.root` ([#15533](sveltejs/kit#15533)) - fix: avoid `inlineDynamicImports` deprecation warning when building the service worker with Vite 8 ([#15550](sveltejs/kit#15550)) - fix: correctly escape backticks when precomputing CSS ([#15593](sveltejs/kit#15593)) - fix: discard obsolete forks before finishing navigation ([#15634](sveltejs/kit#15634)) - chore: tighten up override implementation ([#15562](sveltejs/kit#15562)) - fix: ensure the default Svelte 5 `error.svelte` file uses runes mode ([#15609](sveltejs/kit#15609)) - fix: deduplicate same-cache-key `batch` calls during SSR ([#15533](sveltejs/kit#15533)) - fix: decrement pending\_count when form callback doesn't call submit() ([#15520](sveltejs/kit#15520)) </details> --- ### Configuration 📅 **Schedule**: (in timezone UTC) - Branch creation - At any time (no schedule defined) - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://codeberg.org/ampmod/aw3/pulls/57 Co-authored-by: AmpMod Bot <ampmod-bot@noreply.codeberg.org> Co-committed-by: AmpMod Bot <ampmod-bot@noreply.codeberg.org>

teemingc added 3 commits March 24, 2026 04:56

wip

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changeset

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types

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teemingc added the types / typescript label Mar 24, 2026

teemingc added 2 commits March 28, 2026 01:33

update svelte-check

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Merge branch 'main' into feat-ts6

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teemingc added 12 commits March 31, 2026 11:33

update svelte-check

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type fixes

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more test fixes

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another one

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another onee

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another oneeee

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fix test

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last one?

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fix test app

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type this

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Merge branch 'main' into feat-ts6

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revert package typescript version

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teemingc added 2 commits March 31, 2026 16:57

try fix ci error

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try

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teemingc commented Mar 31, 2026

View reviewed changes

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teemingc added 2 commits March 31, 2026 17:07

Apply suggestion from @teemingc

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try

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teemingc marked this pull request as ready for review March 31, 2026 10:12

danieldietzler mentioned this pull request Mar 31, 2026

chore(deps): update dependency typescript to v6 immich-app/data.immich.app#303

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teemingc added 2 commits March 31, 2026 23:26

update eslint-config

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Merge branch 'main' into feat-ts6

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Rich-Harris approved these changes Apr 1, 2026

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teemingc merged commit c2e8f04 into main Apr 1, 2026
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teemingc deleted the feat-ts6 branch April 1, 2026 02:05

This was referenced Apr 1, 2026

Version Packages #15552

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Version Packages (next) #15311

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rgieseke mentioned this pull request Apr 13, 2026

TypeScript 6 compatibility mhkeller/layercake#393

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DominikRusso mentioned this pull request Apr 17, 2026

Create release for @sveltejs/package #15720

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