From 18ca2e90ac866a427774738a5cd7d1668c18a724 Mon Sep 17 00:00:00 2001
From: Jacob Wright <jacob@dabblewriter.com>
Date: Thu, 16 Jan 2025 11:12:10 -0700
Subject: [PATCH] Recommended fix for CORs immutable headers issue

Fixes https://github.com/kwhitley/itty-router/issues/261 by creating a new response with mutable headers and avoiding duplicating the body. The correct fix for what https://github.com/kwhitley/itty-router/commit/74f63abb25d12666e7c05e5e82fcf7432f8dbda4#diff-a1624121bc1fee18f8a5c2b2f907f01ba9c56a50068007e4c5da2911e91ea6df was trying to achieve.
---
 src/cors.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cors.ts b/src/cors.ts
index 9b08608..3349a98 100644
--- a/src/cors.ts
+++ b/src/cors.ts
@@ -78,7 +78,7 @@ export const cors = (options: CorsOptions = {}) => {
       || response.status == 101
     ) return response
 
-    return appendHeadersAndReturn(response.clone(), {
+    return appendHeadersAndReturn(new Response(response.body, response), {
       'access-control-allow-origin': getAccessControlOrigin(request),
       'access-control-allow-credentials': credentials,
     })