From 315f455623c667b998da57c9491d3b2769275f3b Mon Sep 17 00:00:00 2001
From: David Sanders <dsanders11@ucsbalum.com>
Date: Wed, 16 Mar 2022 03:33:12 -0700
Subject: [PATCH] chore: partially revert #21552

---
 lib/browser/api/net.ts                       | 33 +++++++-------------
 shell/browser/api/electron_api_url_loader.cc |  3 +-
 typings/internal-ambient.d.ts                |  1 +
 3 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/lib/browser/api/net.ts b/lib/browser/api/net.ts
index 80351c0cdbaae..08a44a4b503cc 100644
--- a/lib/browser/api/net.ts
+++ b/lib/browser/api/net.ts
@@ -59,29 +59,18 @@ class IncomingMessage extends Readable {
 
   get headers () {
     const filteredHeaders: Record<string, string | string[]> = {};
-    const { rawHeaders } = this._responseHead;
-    rawHeaders.forEach(header => {
-      const keyLowerCase = header.key.toLowerCase();
-      if (Object.prototype.hasOwnProperty.call(filteredHeaders, keyLowerCase) &&
-          discardableDuplicateHeaders.has(keyLowerCase)) {
-        // do nothing with discardable duplicate headers
+    const { headers } = this._responseHead;
+    Object.keys(headers).forEach(header => {
+      if (header === 'set-cookie') {
+        // keep set-cookie as an array per Node.js rules
+        // see https://nodejs.org/api/http.html#http_message_headers
+        filteredHeaders[header] = headers[header];
+      } else if (discardableDuplicateHeaders.has(header)) {
+        // do not join discardable duplicate headers, instead keep the first
+        filteredHeaders[header] = headers[header][0];
       } else {
-        if (keyLowerCase === 'set-cookie') {
-          // keep set-cookie as an array per Node.js rules
-          // see https://nodejs.org/api/http.html#http_message_headers
-          if (Object.prototype.hasOwnProperty.call(filteredHeaders, keyLowerCase)) {
-            (filteredHeaders[keyLowerCase] as string[]).push(header.value);
-          } else {
-            filteredHeaders[keyLowerCase] = [header.value];
-          }
-        } else {
-          // for non-cookie headers, the values are joined together with ', '
-          if (Object.prototype.hasOwnProperty.call(filteredHeaders, keyLowerCase)) {
-            filteredHeaders[keyLowerCase] += `, ${header.value}`;
-          } else {
-            filteredHeaders[keyLowerCase] = header.value;
-          }
-        }
+        // for everything else, the values are joined together with ', '
+        filteredHeaders[header] = headers[header].join(', ');
       }
     });
     return filteredHeaders;
diff --git a/shell/browser/api/electron_api_url_loader.cc b/shell/browser/api/electron_api_url_loader.cc
index 86a7eb0cc3f92..15b378c55ac56 100644
--- a/shell/browser/api/electron_api_url_loader.cc
+++ b/shell/browser/api/electron_api_url_loader.cc
@@ -578,9 +578,8 @@ void SimpleURLLoaderWrapper::OnResponseStarted(
   gin::Dictionary dict = gin::Dictionary::CreateEmpty(isolate);
   dict.Set("statusCode", response_head.headers->response_code());
   dict.Set("statusMessage", response_head.headers->GetStatusText());
+  dict.Set("headers", response_head.headers.get());
   dict.Set("httpVersion", response_head.headers->GetHttpVersion());
-  // Note that |response_head.headers| are filtered by Chromium and should not
-  // be used here.
   DCHECK(!response_head.raw_response_headers.empty());
   dict.Set("rawHeaders", response_head.raw_response_headers);
   Emit("response-started", final_url, dict);
diff --git a/typings/internal-ambient.d.ts b/typings/internal-ambient.d.ts
index 92d707c8edacc..e7a362ba976d0 100644
--- a/typings/internal-ambient.d.ts
+++ b/typings/internal-ambient.d.ts
@@ -147,6 +147,7 @@ declare namespace NodeJS {
     statusCode: number;
     statusMessage: string;
     httpVersion: { major: number, minor: number };
+    headers: Record<string, string[]>;
     rawHeaders: { key: string, value: string }[];
   };