fix(preact,svelte): empty target container before rendering `client:only` island (#13470)

* fix(preact,svelte): empty target container before rendering `client:only` island

* Remove log

1 files changed, 11 insertions, 5 deletions

diff --git a/packages/integrations/preact/src/client.ts b/packages/integrations/preact/src/client.ts
index 32fdc9888..40475acc8 100644
--- a/packages/integrations/preact/src/client.ts
+++ b/packages/integrations/preact/src/client.ts
@@ -49,13 +49,19 @@ export default (element: HTMLElement) =>
 			}
 		}
 
-		const bootstrap = client !== 'only' ? hydrate : render;
-
-		bootstrap(
-			h(Component, props, children != null ? h(StaticHtml, { value: children }) : children),
-			element,
+		const child = h(
+			Component,
+			props,
+			children != null ? h(StaticHtml, { value: children }) : children,
 		);
 
+		if (client === 'only') {
+			element.innerHTML = '';
+			render(child, element);
+		} else {
+			hydrate(child, element);
+		}
+
 		// Preact has no "unmount" option, but you can use `render(null, element)`
 		element.addEventListener('astro:unmount', () => render(null, element), { once: true });
 	};