stylelint · jeddy3 · Nov 13, 2025 · Nov 8, 2025 · Nov 8, 2025 · Nov 8, 2025
diff --git a/.changeset/chubby-donkeys-remain.md b/.changeset/chubby-donkeys-remain.md
@@ -0,0 +1,5 @@
+---
+"stylelint": patch
+---
+
+Added: support for `customSyntax` with function export
diff --git a/lib/__tests__/standalone-syntax.test.mjs b/lib/__tests__/standalone-syntax.test.mjs
@@ -116,6 +116,19 @@ it('standalone with custom syntax as npm package', async () => {
 	expect(results[0].warnings[0]).toMatchObject({ line: 2, column: 3, rule: 'block-no-empty' });
 });
 
+it('standalone with custom syntax as npm package and function export', async () => {
+	const { results } = await standalone({
+		config: config(),
+		customSyntax: (await import('postcss-html')).default,
+		code: '<style>foo {}</style>',
+		formatter: stringFormatter,
+	});
+
+	expect(results).toHaveLength(1);
+	expect(results[0].warnings).toHaveLength(1);
+	expect(results[0].warnings[0]).toMatchObject({ line: 1, column: 12, rule: 'block-no-empty' });
+});
+
 it('rejects on unknown custom syntax option', async () => {
 	await expect(
 		standalone({

diff --git a/lib/getPostcssResult.cjs b/lib/getPostcssResult.cjs
diff --git a/lib/getPostcssResult.mjs b/lib/getPostcssResult.mjs
@@ -104,7 +104,7 @@ async function getCustomSyntax(customSyntax, basedir) {
 		return resolved;
 	}
 
-	if (typeof customSyntax === 'object') {
+	if (typeof customSyntax === 'object' || typeof customSyntax === 'function') {
 		if (typeof customSyntax.parse === 'function') {
 			return { ...customSyntax };
 		}