From a916188899a7527c0b5f2f22784217b292bbb56c Mon Sep 17 00:00:00 2001
From: Hyunbin <47051820+hyunbinseo@users.noreply.github.com>
Date: Sun, 4 Aug 2024 13:13:03 +0900
Subject: [PATCH] docs: handle immutable headers error

---
 documentation/docs/30-advanced/20-hooks.md | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/documentation/docs/30-advanced/20-hooks.md b/documentation/docs/30-advanced/20-hooks.md
index 1dfab113a7f8..374bc7e4b43e 100644
--- a/documentation/docs/30-advanced/20-hooks.md
+++ b/documentation/docs/30-advanced/20-hooks.md
@@ -61,7 +61,14 @@ export async function handle({ event, resolve }) {
 	event.locals.user = await getUserInformation(event.cookies.get('sessionid'));
 
 	const response = await resolve(event);
-	response.headers.set('x-custom-header', 'potato');
+
+	try {
+		response.headers.set('x-custom-header', 'potato');
+	} catch {
+		// Response objects can have immutable headers.
+		// Modifying immutable headers throws a TypeError.
+		// e.g. Response.redirect() returned from an endpoint.
+	}
 
 	return response;
 }