svelte@5.57.1
sveltejs/sveltesvelte@5.57.1Sep 18, 2026by github-actions[bot]
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AI Summary
This patch release focuses on stabilizing the compiler and runtime, primarily addressing issues in server-side rendering (SSR), event handling cleanup, and parser performance. Key improvements include optimizations to reduce garbage collection, fixes for reactive state proxy ownership, and enhancements to CSS scoping.
Key Highlights
- Reduced garbage collection during SSR render results
- Improved parser performance by optimizing interactions with Acorn
- Fixed deferred event listener cleanup during component destruction
- Enhanced CSS scoping to preserve global styles in components
Full Release Notes
### Patch Changes - fix: cancel deferred event listeners during cleanup ([#18749](https://github.com/sveltejs/svelte/pull/18749)) - fix: preserve global CSS in components without scopable elements ([#18793](https://github.com/sveltejs/svelte/pull/18793)) - fix: reduce SSR render result garbage collection ([#18798](https://github.com/sveltejs/svelte/pull/18798)) - fix: resolve the fallback of an each block in the enclosing scope ([#18803](https://github.com/sveltejs/svelte/pull/18803)) - perf: speed up parser interactions with Acorn or avoid them where possible ([#18740](https://github.com/sveltejs/svelte/pull/18740)) - fix: prevent effect tree of batches from interfering with each other ([#18508](https://github.com/sveltejs/svelte/pull/18508)) - fix: serialize input default values during server rendering ([#18733](https://github.com/sveltejs/svelte/pull/18733)) - fix: remove `WAS_MARKED` flag in favor of `Set` ([#18127](https://github.com/sveltejs/svelte/pull/18127)) - fix: throw `set_context_after_init` when `setContext` is called after an `await` during SSR ([#18739](https://github.com/sveltejs/svelte/pull/18739)) - fix: make Object.hasOwn reactive for state proxy ownership changes ([#18838](https://github.com/sveltejs/svelte/pull/18838)) - fix: keep `$state.eager` when used as a variable initializer ([#18809](https://github.com/sveltejs/svelte/pull/18809)) - perf: avoid regex matching in parser where possible ([#18736](https://github.com/sveltejs/svelte/pull/18736)) - fix: in non-async mode, only push variable to current_sources when active_reaction is updating ([#18550](https://github.com/sveltejs/svelte/pull/18550)) - fix: recognise `aria-braillelabel` and `aria-brailleroledescription` as known ARIA attributes ([#18765](https://github.com/sveltejs/svelte/pull/18765))
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