1 files changed, 61 insertions, 0 deletions
diff --git a/packages/integrations/preact/src/client.ts b/packages/integrations/preact/src/client.ts
new file mode 100644
index 000000000..32fdc9888
--- /dev/null
+++ b/packages/integrations/preact/src/client.ts
@@ -0,0 +1,61 @@
+import { h, hydrate, render } from 'preact';
+import StaticHtml from './static-html.js';
+import type { SignalLike } from './types.js';
+
+const sharedSignalMap = new Map<string, SignalLike>();
+
+export default (element: HTMLElement) =>
+	async (
+		Component: any,
+		props: Record<string, any>,
+		{ default: children, ...slotted }: Record<string, any>,
+		{ client }: Record<string, string>,
+	) => {
+		if (!element.hasAttribute('ssr')) return;
+		for (const [key, value] of Object.entries(slotted)) {
+			props[key] = h(StaticHtml, { value, name: key });
+		}
+		let signalsRaw = element.dataset.preactSignals;
+		if (signalsRaw) {
+			const { signal } = await import('@preact/signals');
+			let signals: Record<string, string | [string, number][]> = JSON.parse(
+				element.dataset.preactSignals!,
+			);
+			for (const [propName, signalId] of Object.entries(signals)) {
+				if (Array.isArray(signalId)) {
+					signalId.forEach(([id, indexOrKeyInProps]) => {
+						const mapValue = props[propName][indexOrKeyInProps];
+						let valueOfSignal = mapValue;
+
+						// not an property key
+						if (typeof indexOrKeyInProps !== 'string') {
+							valueOfSignal = mapValue[0];
+							indexOrKeyInProps = mapValue[1];
+						}
+
+						if (!sharedSignalMap.has(id)) {
+							const signalValue = signal(valueOfSignal);
+							sharedSignalMap.set(id, signalValue);
+						}
+						props[propName][indexOrKeyInProps] = sharedSignalMap.get(id);
+					});
+				} else {
+					if (!sharedSignalMap.has(signalId)) {
+						const signalValue = signal(props[propName]);
+						sharedSignalMap.set(signalId, signalValue);
+					}
+					props[propName] = sharedSignalMap.get(signalId);
+				}
+			}
+		}
+
+		const bootstrap = client !== 'only' ? hydrate : render;
+
+		bootstrap(
+			h(Component, props, children != null ? h(StaticHtml, { value: children }) : children),
+			element,
+		);
+
+		// Preact has no "unmount" option, but you can use `render(null, element)`
+		element.addEventListener('astro:unmount', () => render(null, element), { once: true });
+	};