fix: invalid vnode._parent value

.changeset/proud-eyes-cheer.md

@@ -0,0 +1,5 @@
+---
+'preact-render-to-string': patch
+---
+
+Fix invalid parent pointer empty value when rendering a suspended vnode

src/index.js

@@ -425,7 +425,7 @@ function _renderToString(
 					return str;
 				} finally {
 					if (afterDiff) afterDiff(vnode);
-					vnode[PARENT] = undefined;
+					vnode[PARENT] = null;
 
 					if (ummountHook) ummountHook(vnode);
 				}
@@ -453,7 +453,7 @@ function _renderToString(
 			const str = renderChildren();
 
 			if (afterDiff) afterDiff(vnode);
-			vnode[PARENT] = undefined;
+			vnode[PARENT] = null;
 
 			if (ummountHook) ummountHook(vnode);
 
@@ -618,7 +618,7 @@ function _renderToString(
 	}
 
 	if (afterDiff) afterDiff(vnode);
-	vnode[PARENT] = undefined;
+	vnode[PARENT] = null;
 	if (ummountHook) ummountHook(vnode);
 
 	// Emit self-closing tag for empty void elements:

test/compat/async.test.js

@@ -1,6 +1,6 @@
 import { renderToStringAsync } from '../../src/index.js';
 import { h } from 'preact';
-import { Suspense } from 'preact/compat';
+import { Suspense, useId } from 'preact/compat';
 import { expect } from 'chai';
 import { createSuspender } from '../utils.js';
 
@@ -165,4 +165,28 @@ describe('Async renderToString', () => {
 
 		expect(msg).to.equal('fail');
 	});
+
+	it('should support hooks', async () => {
+		const { suspended, getResolved } = createSuspender();
+
+		function Suspender() {
+			const id = useId();
+
+			if (!getResolved()) {
+				throw suspended.promise;
+			}
+
+			return <p>{typeof id === 'string' ? 'ok' : 'fail'}</p>;
+		}
+
+		const promise = renderToStringAsync(
+			<Suspense fallback={<div>loading...</div>}>
+				<Suspender />
+			</Suspense>
+		);
+
+		suspended.resolve();
+		const rendered = await promise;
+		expect(rendered).to.equal('<p>ok</p>');
+	});
 });