feat: svelte head body separation for nested components in <svelte:head> tag #17324
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- Fix server-side rendering (SSR) by creating a capture renderer in the head() function that only pushes head content to the parent renderer, discarding body output - Add collect_sync() public method to Renderer for synchronous content collection - Fix client-side rendering (CSR) by filtering non-head-specific elements after rendering in head blocks, moving body elements (div, span, etc.) to the body while keeping head-specific elements (script, meta, link, style, title, etc.) in the head This ensures that when a component with both <svelte:head> and body content is placed inside a parent <svelte:head>, only the nested component's head content appears in the document head, and body content correctly appears in the document body. Fixes: Components rendering inside svelte:head had body content leaking into head section
…re moved to body if the nested component has any
🦋 Changeset detectedLatest commit: e8f6c10 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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Contributor Author
| Playground with fix |
7nik reviewed Dec 7, 2025
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| block(() => render_fn(anchor), HEAD_EFFECT); | ||
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| // After rendering, check if non-head elements were added and move them to body |
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I very doubt this logic makes sense. Aside from "Why do you mix head and body elements?", these elements became un-cleanable in case the component/head is wrapped in #if or something else dynamic. And probably breaks other blocks like #each.
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| Thanks but this isn't a useful feature. A component inside a |
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feat:,fix:,chore:, ordocs:.packages/svelte/src, add a changeset (npx changeset).Tests and linting
pnpm testand lint the project withpnpm lintthis PR fixes 9163