Svelte Release Notes & Changelog

Patch Changes

• fix: don't create async deriveds for a component destroyed while waiting for its top-level await (#18931)
• fix: prevent untracked derived reads from retaining disconnected dependencies (#18829)
• fix: error if {:else} is followed by another {:else} or {:else if ...} (#18900)
• fix: avoid tracking SvelteURLSearchParams during URL updates (#18791)
• fix: restore hydration state when custom element attribute updates throw (#18467)
• fix: attach event handlers that are assigned after a top-level await in production (#18933)

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Patch Changes

• fix: cancel deferred event listeners during cleanup (#18749)
• fix: preserve global CSS in components without scopable elements (#18793)
• fix: reduce SSR render result garbage collection (#18798)
• fix: resolve the fallback of an each block in the enclosing scope (#18803)
• perf: speed up parser interactions with Acorn or avoid them where possible (#18740)
• fix: prevent effect tree of batches from interfering with each other (#18508)
• fix: serialize input default values during server rendering (#18733)
• fix: remove WAS_MARKED flag in favor of Set (#18127)

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Minor Changes

• feat: export RenderOutput, SyncRenderOutput, Csp and Sha256Source from svelte/server (#18648)
• feat: add has function to createContext (#18472)
• feat: support defaultValue on <select> (#18591)
• feat: add getOrInsert/getOrInsertComputed to SvelteMap (#18728)

Patch Changes

• fix: block template store subscriptions on the promise that assigns the store (#18582)
• fix: route $derived teardown errors through invoke_error_boundary (#18486)
• fix: track SvelteDate snapshots in reactions (#18700)
• fix: remove <svelte:head> anchors on unmount (#18697)

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Patch Changes

• fix: preserve CSS escape sequences when printing selectors (#18667)
• fix: parse :nth-child(2n of.foo) where of is not followed by whitespace (#18611)
• fix: transform expressions inside labeled statements during server compilation (#18617)
• docs: clarify that context lookup includes the current component and all ancestors (#18581)
• fix: apply CSS custom properties with falsy values on components (#18634)
• fix: correctly print {#await ... catch x} et al (#18645)
• fix: ignore comments of Program node during migration script (#18656)
• fix: reliably resolve append_style to its correct root (#18614)

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Patch Changes

• fix: skip controlled each fast path while another batch is pending (#18625)
• fix: better whitespace handling inside printer (#18638)
• fix: don't duplicate comments in attributes (#18636)
• fix: preserve CSS comments in the AST printer (#18637)

Patch Changes

• fix: call onerror and provide a working reset when hydrating a failed boundary (#18556)
• fix: preserve select selection when spread attributes omit value (#18561)

Patch Changes

• chore: provide indent option for print (#18474)

Patch Changes

• perf: skip unnecessary blocker analysis when compiling components without top-level await (#18548)
• fix: rerun derived that had an abort controller on reconnection (#18551)

Patch Changes

• chore: drop dead code that make TSGO fail (#18496)
• fix: don't (re)connect deriveds when read inside branch/root effects (#18527)
• fix: skip unnecessary derived effect in earlier batch (#18525)
• fix: avoid declaration tag warning in event handlers (#18500)
• fix: abort deriveds own AbortSignal when it disconnects (#18400)
• fix: ensure $state.eager() is correctly transormed for SSR output (#18530)
• fix: correctly transform declaration tags during SSR (#18492)
• fix: transform computed keys in keyed {#each} destructuring patterns (#18521)

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