From 62c87e4204e16e615c04377e254e7ead5a93e3a2 Mon Sep 17 00:00:00 2001
From: Nathan Sarang-Walters <nwalters512@gmail.com>
Date: Tue, 30 Sep 2025 10:30:58 -0700
Subject: [PATCH 1/2] Preserve whitespace for pre/textarea when pretty-printing

---
 .changeset/rude-apes-taste.md |  5 +++++
 package-lock.json             | 36 +++--------------------------------
 src/pretty.js                 | 21 ++++++++++++++------
 test/pretty.test.jsx          | 19 ++++++++++++++++++
 test/render.test.jsx          |  7 +++++++
 5 files changed, 49 insertions(+), 39 deletions(-)
 create mode 100644 .changeset/rude-apes-taste.md

diff --git a/.changeset/rude-apes-taste.md b/.changeset/rude-apes-taste.md
new file mode 100644
index 00000000..40e00c07
--- /dev/null
+++ b/.changeset/rude-apes-taste.md
@@ -0,0 +1,5 @@
+---
+'preact-render-to-string': patch
+---
+
+Preserve whitespace in `<pre>`/`<textarea>` when using `pretty: true`
diff --git a/package-lock.json b/package-lock.json
index a5ede80e..db843953 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
 	"name": "preact-render-to-string",
-	"version": "6.5.13",
+	"version": "6.6.2",
 	"lockfileVersion": 3,
 	"requires": true,
 	"packages": {
 		"": {
 			"name": "preact-render-to-string",
-			"version": "6.5.13",
+			"version": "6.6.2",
 			"license": "MIT",
 			"devDependencies": {
 				"@babel/plugin-transform-react-jsx": "^7.12.12",
@@ -32,7 +32,7 @@
 				"web-streams-polyfill": "^3.2.1"
 			},
 			"peerDependencies": {
-				"preact": ">=10 || >= 11"
+				"preact": ">=10 || >= 11.0.0-0"
 			}
 		},
 		"node_modules/@babel/code-frame": {
@@ -13378,21 +13378,6 @@
 				}
 			}
 		},
-		"node_modules/vite-node/node_modules/yaml": {
-			"version": "2.8.0",
-			"resolved": "https://registry.npmjs.org/yaml/-/yaml-2.8.0.tgz",
-			"integrity": "sha512-4lLa/EcQCB0cJkyts+FpIRx5G/llPxfP6VQU5KByHEhLxY3IJCH0f0Hy1MHI8sClTvsIb8qwRJ6R/ZdlDJ/leQ==",
-			"dev": true,
-			"license": "ISC",
-			"optional": true,
-			"peer": true,
-			"bin": {
-				"yaml": "bin.mjs"
-			},
-			"engines": {
-				"node": ">= 14.6"
-			}
-		},
 		"node_modules/vitest": {
 			"version": "3.2.4",
 			"resolved": "https://registry.npmjs.org/vitest/-/vitest-3.2.4.tgz",
@@ -13673,21 +13658,6 @@
 				}
 			}
 		},
-		"node_modules/vitest/node_modules/yaml": {
-			"version": "2.8.0",
-			"resolved": "https://registry.npmjs.org/yaml/-/yaml-2.8.0.tgz",
-			"integrity": "sha512-4lLa/EcQCB0cJkyts+FpIRx5G/llPxfP6VQU5KByHEhLxY3IJCH0f0Hy1MHI8sClTvsIb8qwRJ6R/ZdlDJ/leQ==",
-			"dev": true,
-			"license": "ISC",
-			"optional": true,
-			"peer": true,
-			"bin": {
-				"yaml": "bin.mjs"
-			},
-			"engines": {
-				"node": ">= 14.6"
-			}
-		},
 		"node_modules/wcwidth": {
 			"version": "1.0.1",
 			"dev": true,
diff --git a/src/pretty.js b/src/pretty.js
index 5c5443ed..5fc197db 100644
--- a/src/pretty.js
+++ b/src/pretty.js
@@ -24,6 +24,7 @@ const UNNAMED = [];
 
 const EMPTY_ARR = [];
 const EMPTY_STR = '';
+const PRESERVE_WHITESPACE_TAGS = new Set(['pre', 'textarea']);
 
 /**
  * Render Preact JSX + Components to a pretty-printed HTML-like string.
@@ -216,6 +217,11 @@ function _renderToStringPretty(
 		propChildren,
 		html;
 
+	const shouldPreserveWhitespace =
+		pretty &&
+		typeof nodeName === 'string' &&
+		PRESERVE_WHITESPACE_TAGS.has(nodeName);
+
 	if (props) {
 		let attrs = Object.keys(props);
 
@@ -349,7 +355,7 @@ function _renderToStringPretty(
 	let children;
 	if (html) {
 		// if multiline, indent.
-		if (pretty && isLargeString(html)) {
+		if (pretty && !shouldPreserveWhitespace && isLargeString(html)) {
 			html = '\n' + indentChar + indent(html, indentChar);
 		}
 		s = s + html;
@@ -357,7 +363,9 @@ function _renderToStringPretty(
 		propChildren != null &&
 		getChildren((children = []), propChildren).length
 	) {
-		let hasLarge = pretty && ~s.indexOf('\n');
+		const shouldPrettyFormatChildren =
+			pretty && !shouldPreserveWhitespace && typeof nodeName === 'string';
+		let hasLarge = shouldPrettyFormatChildren && ~s.indexOf('\n');
 		let lastWasText = false;
 
 		for (let i = 0; i < children.length; i++) {
@@ -379,11 +387,12 @@ function _renderToStringPretty(
 						selectValue
 					);
 
-				if (pretty && !hasLarge && isLargeString(ret)) hasLarge = true;
+				if (shouldPrettyFormatChildren && !hasLarge && isLargeString(ret))
+					hasLarge = true;
 
 				// Skip if we received an empty string
 				if (ret) {
-					if (pretty) {
+					if (shouldPrettyFormatChildren) {
 						let isText = ret.length > 0 && ret[0] != '<';
 
 						// We merge adjacent text nodes, otherwise each piece would be printed
@@ -401,7 +410,7 @@ function _renderToStringPretty(
 				}
 			}
 		}
-		if (pretty && hasLarge) {
+		if (shouldPrettyFormatChildren && hasLarge) {
 			for (let i = pieces.length; i--; ) {
 				pieces[i] = '\n' + indentChar + indent(pieces[i], indentChar);
 			}
@@ -419,7 +428,7 @@ function _renderToStringPretty(
 	if (isVoid && !children && !html) {
 		s = s.replace(/>$/, ' />');
 	} else {
-		if (pretty && ~s.indexOf('\n')) s = s + '\n';
+		if (pretty && !shouldPreserveWhitespace && ~s.indexOf('\n')) s = s + '\n';
 		s = s + `</${nodeName}>`;
 	}
 
diff --git a/test/pretty.test.jsx b/test/pretty.test.jsx
index 69ee510b..e2c9fa4c 100644
--- a/test/pretty.test.jsx
+++ b/test/pretty.test.jsx
@@ -215,6 +215,25 @@ describe('pretty', () => {
 		);
 	});
 
+	it('should not add whitespace to pre tag children', () => {
+		let rendered = prettyRender(
+			<pre>
+				<code>hello</code>
+			</pre>,
+			{ jsx: false }
+		);
+
+		expect(rendered).to.equal(`<pre><code>hello</code></pre>`);
+	});
+
+	it('should maintain whitespace in textarea tag', () => {
+		let rendered = prettyRender(<textarea>{'  hello\nworld  '}</textarea>, {
+			jsx: false
+		});
+
+		expect(rendered).to.equal(`<textarea>  hello\nworld  </textarea>`);
+	});
+
 	describe('Attribute casing', () => {
 		it('should have correct SVG casing', () => {
 			for (let name in svgAttributes) {
diff --git a/test/render.test.jsx b/test/render.test.jsx
index c189a39e..19dea6b0 100644
--- a/test/render.test.jsx
+++ b/test/render.test.jsx
@@ -243,6 +243,13 @@ describe('render', () => {
 			expect(rendered).to.equal(expected);
 		});
 
+		it('should serialize textarea value with leading/trailing whitespace', () => {
+			let rendered = render(<textarea value={`  a\nb  `} />),
+				expected = `<textarea>  a\nb  </textarea>`;
+
+			expect(rendered).to.equal(expected);
+		});
+
 		it('should escape textarea value', () => {
 			let rendered = render(<textarea value={`a&b"c`} />),
 				expected = `<textarea>a&amp;b&quot;c</textarea>`;

From 96dfd13462f2fb9a63c66198d69d70ed0eecde74 Mon Sep 17 00:00:00 2001
From: Nathan Sarang-Walters <nwalters512@gmail.com>
Date: Tue, 30 Sep 2025 14:11:26 -0700
Subject: [PATCH 2/2] Update lockfile

---
 package-lock.json | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/package-lock.json b/package-lock.json
index db843953..31da0044 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -13378,6 +13378,21 @@
 				}
 			}
 		},
+		"node_modules/vite-node/node_modules/yaml": {
+			"version": "2.8.1",
+			"resolved": "https://registry.npmjs.org/yaml/-/yaml-2.8.1.tgz",
+			"integrity": "sha512-lcYcMxX2PO9XMGvAJkJ3OsNMw+/7FKes7/hgerGUYWIoWu5j/+YQqcZr5JnPZWzOsEBgMbSbiSTn/dv/69Mkpw==",
+			"dev": true,
+			"license": "ISC",
+			"optional": true,
+			"peer": true,
+			"bin": {
+				"yaml": "bin.mjs"
+			},
+			"engines": {
+				"node": ">= 14.6"
+			}
+		},
 		"node_modules/vitest": {
 			"version": "3.2.4",
 			"resolved": "https://registry.npmjs.org/vitest/-/vitest-3.2.4.tgz",
@@ -13658,6 +13673,21 @@
 				}
 			}
 		},
+		"node_modules/vitest/node_modules/yaml": {
+			"version": "2.8.1",
+			"resolved": "https://registry.npmjs.org/yaml/-/yaml-2.8.1.tgz",
+			"integrity": "sha512-lcYcMxX2PO9XMGvAJkJ3OsNMw+/7FKes7/hgerGUYWIoWu5j/+YQqcZr5JnPZWzOsEBgMbSbiSTn/dv/69Mkpw==",
+			"dev": true,
+			"license": "ISC",
+			"optional": true,
+			"peer": true,
+			"bin": {
+				"yaml": "bin.mjs"
+			},
+			"engines": {
+				"node": ">= 14.6"
+			}
+		},
 		"node_modules/wcwidth": {
 			"version": "1.0.1",
 			"dev": true,