1 files changed, 76 insertions, 0 deletions
diff --git a/packages/integrations/svelte/src/server.ts b/packages/integrations/svelte/src/server.ts
new file mode 100644
index 000000000..14f869228
--- /dev/null
+++ b/packages/integrations/svelte/src/server.ts
@@ -0,0 +1,76 @@
+import type { AstroComponentMetadata, NamedSSRLoadedRendererValue } from 'astro';
+import { createRawSnippet } from 'svelte';
+import { render } from 'svelte/server';
+import { incrementId } from './context.js';
+import type { RendererContext } from './types.js';
+
+function check(Component: any) {
+	if (typeof Component !== 'function') return false;
+	// Svelte 5 generated components always accept a `$$payload` prop.
+	// This assumes that the SSR build does not minify it (which Astro enforces by default).
+	// This isn't the best check, but the only other option otherwise is to try to render the
+	// component, which is taxing. We'll leave it as a last resort for the future for now.
+	return Component.toString().includes('$$payload');
+}
+
+function needsHydration(metadata?: AstroComponentMetadata) {
+	// Adjust how this is hydrated only when the version of Astro supports `astroStaticSlot`
+	return metadata?.astroStaticSlot ? !!metadata.hydrate : true;
+}
+
+async function renderToStaticMarkup(
+	this: RendererContext,
+	Component: any,
+	props: Record<string, any>,
+	slotted: Record<string, any>,
+	metadata?: AstroComponentMetadata,
+) {
+	const tagName = needsHydration(metadata) ? 'astro-slot' : 'astro-static-slot';
+
+	let children = undefined;
+	let $$slots: Record<string, any> | undefined = undefined;
+	let idPrefix;
+	if (this && this.result) {
+		idPrefix = incrementId(this.result);
+	}
+	const renderProps: Record<string, any> = {};
+	for (const [key, value] of Object.entries(slotted)) {
+		// Legacy slot support
+		$$slots ??= {};
+		if (key === 'default') {
+			$$slots.default = true;
+			children = createRawSnippet(() => ({
+				render: () => `<${tagName}>${value}</${tagName}>`,
+			}));
+		} else {
+			$$slots[key] = createRawSnippet(() => ({
+				render: () => `<${tagName} name="${key}">${value}</${tagName}>`,
+			}));
+		}
+		// @render support for Svelte ^5.0
+		const slotName = key === 'default' ? 'children' : key;
+		renderProps[slotName] = createRawSnippet(() => ({
+			render: () => `<${tagName}${key !== 'default' ? ` name="${key}"` : ''}>${value}</${tagName}>`,
+		}));
+	}
+
+	const result = render(Component, {
+		props: {
+			...props,
+			children,
+			$$slots,
+			...renderProps,
+		},
+		idPrefix,
+	});
+	return { html: result.body };
+}
+
+const renderer: NamedSSRLoadedRendererValue = {
+	name: '@astrojs/svelte',
+	check,
+	renderToStaticMarkup,
+	supportsAstroStaticSlot: true,
+};
+
+export default renderer;