From 63de6d200b9b04d9e0782de84ff63f7265c0d433 Mon Sep 17 00:00:00 2001
From: Khafra <42794878+KhafraDev@users.noreply.github.com>
Date: Mon, 2 May 2022 14:21:37 -0400
Subject: [PATCH 1/4] fix(Request): allow passing Headers instance to
 init.headers

---
 lib/fetch/request.js  |  7 +++----
 test/fetch/request.js | 35 ++++++++++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/lib/fetch/request.js b/lib/fetch/request.js
index 24210e59044..ee7563cc9da 100644
--- a/lib/fetch/request.js
+++ b/lib/fetch/request.js
@@ -420,10 +420,9 @@ class Request {
       // 4. If headers is a Headers object, then for each header in its header
       // list, append header’s name/header’s value to this’s headers.
       if (headers instanceof Headers) {
-        // TODO (fix): Why doesn't this work?
-        // for (const [key, val] of headers[kHeadersList]) {
-        //   this[kHeaders].append(key, val)
-        // }
+        for (const [key, val] of headers) {
+          this[kHeaders].append(key, val)
+        }
 
         this[kState].headersList = new HeadersList([
           ...this[kState].headersList,
diff --git a/test/fetch/request.js b/test/fetch/request.js
index 5c84f754150..c2ab7fab200 100644
--- a/test/fetch/request.js
+++ b/test/fetch/request.js
@@ -4,7 +4,8 @@
 
 const { test } = require('tap')
 const {
-  Request
+  Request,
+  Headers
 } = require('../../')
 const { kState } = require('../../lib/fetch/symbols.js')
 
@@ -272,3 +273,35 @@ test('post aborted signal cloned', t => {
   })
   ac.abort()
 })
+
+test('Passing headers in init', (t) => {
+  // https://github.com/nodejs/undici/issues/1400
+  t.test('Headers instance', (t) => {
+    const req = new Request('http://localhost', {
+      headers: new Headers({ key: 'value' })
+    })
+
+    t.equal(req.headers.get('key'), 'value')
+    t.end()
+  })
+
+  t.test('key:value object', (t) => {
+    const req = new Request('http://localhost', {
+      headers: { key: 'value' }
+    })
+
+    t.equal(req.headers.get('key'), 'value')
+    t.end()
+  })
+
+  t.test('[key, value][]', (t) => {
+    const req = new Request('http://localhost', {
+      headers: [['key', 'value']]
+    })
+
+    t.equal(req.headers.get('key'), 'value')
+    t.end()
+  })
+
+  t.end()
+})

From 2569544a67c30d1e74177c51b2105a4181f09c74 Mon Sep 17 00:00:00 2001
From: Khafra <42794878+KhafraDev@users.noreply.github.com>
Date: Mon, 2 May 2022 14:28:14 -0400
Subject: [PATCH 2/4] fix(Request): remove unnecessary condition

---
 lib/fetch/request.js | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/lib/fetch/request.js b/lib/fetch/request.js
index ee7563cc9da..25395c18516 100644
--- a/lib/fetch/request.js
+++ b/lib/fetch/request.js
@@ -423,11 +423,6 @@ class Request {
         for (const [key, val] of headers) {
           this[kHeaders].append(key, val)
         }
-
-        this[kState].headersList = new HeadersList([
-          ...this[kState].headersList,
-          ...headers[kHeadersList]
-        ])
       } else {
         // 5. Otherwise, fill this’s headers with headers.
         fillHeaders(this[kState].headersList, headers)

From d19f7567acbbc322778678b8e9b46aa2cd4b2f38 Mon Sep 17 00:00:00 2001
From: Khafra <42794878+KhafraDev@users.noreply.github.com>
Date: Mon, 2 May 2022 14:53:34 -0400
Subject: [PATCH 3/4] test: fix node-fetch test failures

---
 lib/fetch/request.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/fetch/request.js b/lib/fetch/request.js
index 25395c18516..9993b81d2d6 100644
--- a/lib/fetch/request.js
+++ b/lib/fetch/request.js
@@ -419,10 +419,12 @@ class Request {
 
       // 4. If headers is a Headers object, then for each header in its header
       // list, append header’s name/header’s value to this’s headers.
-      if (headers instanceof Headers) {
+      if (headers.constructor.name === 'Headers') {
         for (const [key, val] of headers) {
           this[kHeaders].append(key, val)
         }
+
+        this[kState].headersList = headers[kHeadersList]
       } else {
         // 5. Otherwise, fill this’s headers with headers.
         fillHeaders(this[kState].headersList, headers)

From 24162cc92572f89623f916df0c8966447d29e361 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sun, 8 May 2022 22:29:50 +0300
Subject: [PATCH 4/4] fixup

---
 lib/fetch/request.js | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/fetch/request.js b/lib/fetch/request.js
index 9993b81d2d6..c17927ee768 100644
--- a/lib/fetch/request.js
+++ b/lib/fetch/request.js
@@ -420,11 +420,9 @@ class Request {
       // 4. If headers is a Headers object, then for each header in its header
       // list, append header’s name/header’s value to this’s headers.
       if (headers.constructor.name === 'Headers') {
-        for (const [key, val] of headers) {
+        for (const [key, val] of headers[kHeadersList] || headers) {
           this[kHeaders].append(key, val)
         }
-
-        this[kState].headersList = headers[kHeadersList]
       } else {
         // 5. Otherwise, fill this’s headers with headers.
         fillHeaders(this[kState].headersList, headers)
@@ -464,7 +462,6 @@ class Request {
       // this’s headers.
       if (contentType && !this[kHeaders].has('content-type')) {
         this[kHeaders].append('content-type', contentType)
-        this[kState].headersList.append('content-type', contentType)
       }
     }