From 0a053f705210f585ce0e0e597920f1f0241110c7 Mon Sep 17 00:00:00 2001
From: Ethan Arrowood <ethan.arrowood@vercel.com>
Date: Tue, 24 Oct 2023 16:32:17 -0600
Subject: [PATCH] improve HeadersInit type

---
 types/fetch.d.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/types/fetch.d.ts b/types/fetch.d.ts
index fa4619c9182..16a4c1654f4 100644
--- a/types/fetch.d.ts
+++ b/types/fetch.d.ts
@@ -50,7 +50,7 @@ export interface SpecIterable<T> {
   [Symbol.iterator](): SpecIterator<T>;
 }
 
-export type HeadersInit = string[][] | Record<string, string | ReadonlyArray<string>> | Headers
+export type HeadersInit = string[][] | Record<string, string | ReadonlyArray<string> | undefined> | Headers
 
 export declare class Headers implements SpecIterable<[string, string]> {
   constructor (init?: HeadersInit)