From e9780abd5c99f5337ae73c987a580418743eeb17 Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Wed, 15 Sep 2021 14:00:13 +0530
Subject: [PATCH 1/8] feat: allow array for `headers` option

---
 lib/Server.js    | 15 ++++++++++++++-
 lib/options.json | 20 ++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/lib/Server.js b/lib/Server.js
index 5d1c6835d5..0e42499cd7 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -490,7 +490,20 @@ class Server {
       options.devMiddleware = {};
     }
 
-    // No need to normalize `headers`
+    // normalize `headers`
+
+    if (
+      typeof options.headers !== "undefined" &&
+      Array.isArray(options.headers)
+    ) {
+      const allHeaders = {};
+
+      options.headers.forEach((header) => {
+        allHeaders[header.key] = header.value;
+      });
+
+      options.headers = allHeaders;
+    }
 
     if (typeof options.historyApiFallback === "undefined") {
       options.historyApiFallback = false;
diff --git a/lib/options.json b/lib/options.json
index b1c6215516..cef66d0149 100644
--- a/lib/options.json
+++ b/lib/options.json
@@ -369,8 +369,28 @@
       "description": "Allows to configure the server's listening socket for TLS (by default, dev server will be served over HTTP).",
       "link": "https://webpack.js.org/configuration/dev-server/#devserverhttps"
     },
+    "HeaderObject": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "key": {
+          "description": "key of header.",
+          "type": "string"
+        },
+        "value": {
+          "description": "value of header.",
+          "type": "string"
+        }
+      }
+    },
     "Headers": {
       "anyOf": [
+        {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/HeaderObject"
+          }
+        },
         {
           "type": "object"
         },

From 4d935faf9a60b326bdfea243e2b234f961e80a56 Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Wed, 15 Sep 2021 14:04:41 +0530
Subject: [PATCH 2/8] test: add validation tests

---
 lib/options.json                              |  3 ++-
 .../validate-options.test.js.snap.webpack4    | 19 +++++++++++++++++--
 .../validate-options.test.js.snap.webpack5    | 19 +++++++++++++++++--
 test/validate-options.test.js                 |  4 ++--
 4 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/lib/options.json b/lib/options.json
index cef66d0149..639ed5c391 100644
--- a/lib/options.json
+++ b/lib/options.json
@@ -389,7 +389,8 @@
           "type": "array",
           "items": {
             "$ref": "#/definitions/HeaderObject"
-          }
+          },
+          "minItems": 1
         },
         {
           "type": "object"
diff --git a/test/__snapshots__/validate-options.test.js.snap.webpack4 b/test/__snapshots__/validate-options.test.js.snap.webpack4
index dd1a5f8e30..79c47d8241 100644
--- a/test/__snapshots__/validate-options.test.js.snap.webpack4
+++ b/test/__snapshots__/validate-options.test.js.snap.webpack4
@@ -223,13 +223,26 @@ exports[`options validate should throw an error on the "devMiddleware" option wi
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverdevmiddleware"
 `;
 
+exports[`options validate should throw an error on the "headers" option with '[]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.headers should be a non-empty array."
+`;
+
+exports[`options validate should throw an error on the "headers" option with '[{"foo":"bar"}]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.headers[0] has an unknown property 'foo'. These properties are valid:
+   object { key?, value? }"
+`;
+
 exports[`options validate should throw an error on the "headers" option with '1' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.headers should be one of these:
-   object { … } | function
+   [object { key?, value? }, ...] (should not have fewer than 1 item) | object { … } | function
    -> Allows to set custom headers on response.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverheaders
    Details:
+    * options.headers should be an array:
+      [object { key?, value? }, ...] (should not have fewer than 1 item)
     * options.headers should be an object:
       object { … }
     * options.headers should be an instance of function."
@@ -238,10 +251,12 @@ exports[`options validate should throw an error on the "headers" option with '1'
 exports[`options validate should throw an error on the "headers" option with 'false' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.headers should be one of these:
-   object { … } | function
+   [object { key?, value? }, ...] (should not have fewer than 1 item) | object { … } | function
    -> Allows to set custom headers on response.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverheaders
    Details:
+    * options.headers should be an array:
+      [object { key?, value? }, ...] (should not have fewer than 1 item)
     * options.headers should be an object:
       object { … }
     * options.headers should be an instance of function."
diff --git a/test/__snapshots__/validate-options.test.js.snap.webpack5 b/test/__snapshots__/validate-options.test.js.snap.webpack5
index dd1a5f8e30..79c47d8241 100644
--- a/test/__snapshots__/validate-options.test.js.snap.webpack5
+++ b/test/__snapshots__/validate-options.test.js.snap.webpack5
@@ -223,13 +223,26 @@ exports[`options validate should throw an error on the "devMiddleware" option wi
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverdevmiddleware"
 `;
 
+exports[`options validate should throw an error on the "headers" option with '[]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.headers should be a non-empty array."
+`;
+
+exports[`options validate should throw an error on the "headers" option with '[{"foo":"bar"}]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.headers[0] has an unknown property 'foo'. These properties are valid:
+   object { key?, value? }"
+`;
+
 exports[`options validate should throw an error on the "headers" option with '1' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.headers should be one of these:
-   object { … } | function
+   [object { key?, value? }, ...] (should not have fewer than 1 item) | object { … } | function
    -> Allows to set custom headers on response.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverheaders
    Details:
+    * options.headers should be an array:
+      [object { key?, value? }, ...] (should not have fewer than 1 item)
     * options.headers should be an object:
       object { … }
     * options.headers should be an instance of function."
@@ -238,10 +251,12 @@ exports[`options validate should throw an error on the "headers" option with '1'
 exports[`options validate should throw an error on the "headers" option with 'false' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.headers should be one of these:
-   object { … } | function
+   [object { key?, value? }, ...] (should not have fewer than 1 item) | object { … } | function
    -> Allows to set custom headers on response.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverheaders
    Details:
+    * options.headers should be an array:
+      [object { key?, value? }, ...] (should not have fewer than 1 item)
     * options.headers should be an object:
       object { … }
     * options.headers should be an instance of function."
diff --git a/test/validate-options.test.js b/test/validate-options.test.js
index 829ed40e84..7bc528b944 100644
--- a/test/validate-options.test.js
+++ b/test/validate-options.test.js
@@ -169,8 +169,8 @@ const tests = {
     failure: [true, false, 123, [], [""]],
   },
   headers: {
-    success: [{}, { foo: "bar" }, () => {}],
-    failure: [false, 1],
+    success: [{}, { foo: "bar" }, () => {}, [{ key: "foo", value: "bar" }]],
+    failure: [false, 1, [], [{ foo: "bar" }]],
   },
   historyApiFallback: {
     success: [{}, true],

From 9cd2cd6ca7fc6cedad0947ae5ce8a9ef9aef5e4e Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Wed, 15 Sep 2021 14:08:07 +0530
Subject: [PATCH 3/8] test: add e2e tests

---
 .../headers.test.js.snap.webpack4             | 10 +++
 .../headers.test.js.snap.webpack5             | 10 +++
 test/e2e/headers.test.js                      | 72 +++++++++++++++++++
 3 files changed, 92 insertions(+)

diff --git a/test/e2e/__snapshots__/headers.test.js.snap.webpack4 b/test/e2e/__snapshots__/headers.test.js.snap.webpack4
index 808f4404ac..c9edf9f641 100644
--- a/test/e2e/__snapshots__/headers.test.js.snap.webpack4
+++ b/test/e2e/__snapshots__/headers.test.js.snap.webpack4
@@ -19,6 +19,16 @@ exports[`headers option as a string should handle GET request with headers: resp
 
 exports[`headers option as a string should handle GET request with headers: response status 1`] = `200`;
 
+exports[`headers option as an array of objects should handle GET request with headers: console messages 1`] = `Array []`;
+
+exports[`headers option as an array of objects should handle GET request with headers: page errors 1`] = `Array []`;
+
+exports[`headers option as an array of objects should handle GET request with headers: response headers x-bar 1`] = `"value2"`;
+
+exports[`headers option as an array of objects should handle GET request with headers: response headers x-foo 1`] = `"value1"`;
+
+exports[`headers option as an array of objects should handle GET request with headers: response status 1`] = `200`;
+
 exports[`headers option as an array should handle GET request with headers as an array: console messages 1`] = `Array []`;
 
 exports[`headers option as an array should handle GET request with headers as an array: page errors 1`] = `Array []`;
diff --git a/test/e2e/__snapshots__/headers.test.js.snap.webpack5 b/test/e2e/__snapshots__/headers.test.js.snap.webpack5
index 808f4404ac..c9edf9f641 100644
--- a/test/e2e/__snapshots__/headers.test.js.snap.webpack5
+++ b/test/e2e/__snapshots__/headers.test.js.snap.webpack5
@@ -19,6 +19,16 @@ exports[`headers option as a string should handle GET request with headers: resp
 
 exports[`headers option as a string should handle GET request with headers: response status 1`] = `200`;
 
+exports[`headers option as an array of objects should handle GET request with headers: console messages 1`] = `Array []`;
+
+exports[`headers option as an array of objects should handle GET request with headers: page errors 1`] = `Array []`;
+
+exports[`headers option as an array of objects should handle GET request with headers: response headers x-bar 1`] = `"value2"`;
+
+exports[`headers option as an array of objects should handle GET request with headers: response headers x-foo 1`] = `"value1"`;
+
+exports[`headers option as an array of objects should handle GET request with headers: response status 1`] = `200`;
+
 exports[`headers option as an array should handle GET request with headers as an array: console messages 1`] = `Array []`;
 
 exports[`headers option as an array should handle GET request with headers as an array: page errors 1`] = `Array []`;
diff --git a/test/e2e/headers.test.js b/test/e2e/headers.test.js
index a921f7f4dd..780c20d88d 100644
--- a/test/e2e/headers.test.js
+++ b/test/e2e/headers.test.js
@@ -66,6 +66,78 @@ describe("headers option", () => {
     });
   });
 
+  describe("as an array of objects", () => {
+    let compiler;
+    let server;
+    let page;
+    let browser;
+    let pageErrors;
+    let consoleMessages;
+
+    beforeEach(async () => {
+      compiler = webpack(config);
+
+      server = new Server(
+        {
+          headers: [
+            {
+              key: "X-Foo",
+              value: "value1",
+            },
+            {
+              key: "X-Bar",
+              value: "value2",
+            },
+          ],
+          port,
+        },
+        compiler
+      );
+
+      await server.start();
+
+      ({ page, browser } = await runBrowser());
+
+      pageErrors = [];
+      consoleMessages = [];
+    });
+
+    afterEach(async () => {
+      await browser.close();
+      await server.stop();
+    });
+
+    it("should handle GET request with headers", async () => {
+      page
+        .on("console", (message) => {
+          consoleMessages.push(message);
+        })
+        .on("pageerror", (error) => {
+          pageErrors.push(error);
+        });
+
+      const response = await page.goto(`http://127.0.0.1:${port}/main.js`, {
+        waitUntil: "networkidle0",
+      });
+
+      expect(response.headers()["x-foo"]).toMatchSnapshot(
+        "response headers x-foo"
+      );
+
+      expect(response.headers()["x-bar"]).toMatchSnapshot(
+        "response headers x-bar"
+      );
+
+      expect(response.status()).toMatchSnapshot("response status");
+
+      expect(consoleMessages.map((message) => message.text())).toMatchSnapshot(
+        "console messages"
+      );
+
+      expect(pageErrors).toMatchSnapshot("page errors");
+    });
+  });
+
   describe("as an array", () => {
     let compiler;
     let server;

From b9400371fa2fb1056355d2551d25ec8f3d7f4436 Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Wed, 15 Sep 2021 14:13:45 +0530
Subject: [PATCH 4/8] docs: add example

---
 examples/headers/array/README.md         | 36 ++++++++++++++++++++++++
 examples/headers/array/app.js            |  6 ++++
 examples/headers/array/webpack.config.js | 22 +++++++++++++++
 3 files changed, 64 insertions(+)
 create mode 100644 examples/headers/array/README.md
 create mode 100644 examples/headers/array/app.js
 create mode 100644 examples/headers/array/webpack.config.js

diff --git a/examples/headers/array/README.md b/examples/headers/array/README.md
new file mode 100644
index 0000000000..3ef60579b1
--- /dev/null
+++ b/examples/headers/array/README.md
@@ -0,0 +1,36 @@
+# headers option as an object
+
+Adds headers to all responses.
+
+**webpack.config.js**
+
+```js
+module.exports = {
+  // ...
+  devServer: {
+    headers: [
+      {
+        key: "X-Foo",
+        value: "value1",
+      },
+      {
+        key: "X-Bar",
+        value: "value2",
+      },
+    ],
+  },
+};
+```
+
+To run this example use the following command:
+
+```console
+npx webpack serve --open
+```
+
+## What should happen
+
+1. The script should open `http://localhost:8080/`.
+2. You should see the text on the page itself change to read `Success!`.
+3. Open the console in your browser's devtools and select the _Network_ tab.
+4. Find `main.js`. The response headers should contain `X-Foo: value1` and `X-Bar: value2`.
diff --git a/examples/headers/array/app.js b/examples/headers/array/app.js
new file mode 100644
index 0000000000..51cf4a396b
--- /dev/null
+++ b/examples/headers/array/app.js
@@ -0,0 +1,6 @@
+"use strict";
+
+const target = document.querySelector("#target");
+
+target.classList.add("pass");
+target.innerHTML = "Success!";
diff --git a/examples/headers/array/webpack.config.js b/examples/headers/array/webpack.config.js
new file mode 100644
index 0000000000..e2ad9d34a0
--- /dev/null
+++ b/examples/headers/array/webpack.config.js
@@ -0,0 +1,22 @@
+"use strict";
+
+// our setup function adds behind-the-scenes bits to the config that all of our
+// examples need
+const { setup } = require("../../util");
+
+module.exports = setup({
+  context: __dirname,
+  entry: "./app.js",
+  devServer: {
+    headers: [
+      {
+        key: "X-Foo",
+        value: "value1",
+      },
+      {
+        key: "X-Bar",
+        value: "value2",
+      },
+    ],
+  },
+});

From fde859a5e8ec29d0951e4e1908a8b2cedbb6683b Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Wed, 15 Sep 2021 14:33:10 +0530
Subject: [PATCH 5/8] refactor: schema

---
 lib/Server.js    | 1 -
 lib/options.json | 3 +++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/Server.js b/lib/Server.js
index 0e42499cd7..eef76a092d 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -491,7 +491,6 @@ class Server {
     }
 
     // normalize `headers`
-
     if (
       typeof options.headers !== "undefined" &&
       Array.isArray(options.headers)
diff --git a/lib/options.json b/lib/options.json
index 639ed5c391..f1c01e5d91 100644
--- a/lib/options.json
+++ b/lib/options.json
@@ -381,6 +381,9 @@
           "description": "value of header.",
           "type": "string"
         }
+      },
+      "cli": {
+        "exclude": true
       }
     },
     "Headers": {

From dbb6de428c963a860228bbbe69e0edfa245b90cc Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Wed, 15 Sep 2021 19:05:22 +0530
Subject: [PATCH 6/8] test: more

---
 lib/Server.js                                 | 26 ++++---
 .../headers.test.js.snap.webpack4             | 10 +++
 .../headers.test.js.snap.webpack5             | 10 +++
 test/e2e/headers.test.js                      | 72 +++++++++++++++++++
 4 files changed, 110 insertions(+), 8 deletions(-)

diff --git a/lib/Server.js b/lib/Server.js
index eef76a092d..7688da5dfc 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -491,17 +491,27 @@ class Server {
     }
 
     // normalize `headers`
-    if (
-      typeof options.headers !== "undefined" &&
-      Array.isArray(options.headers)
-    ) {
+    if (typeof options.headers !== "undefined") {
       const allHeaders = {};
 
-      options.headers.forEach((header) => {
-        allHeaders[header.key] = header.value;
-      });
+      if (Array.isArray(options.headers)) {
+        options.headers.forEach((header) => {
+          allHeaders[header.key] = header.value;
+        });
+        options.headers = allHeaders;
+      }
 
-      options.headers = allHeaders;
+      if (typeof options.headers === "function") {
+        const returnedHeaders = options.headers();
+
+        if (Array.isArray(returnedHeaders)) {
+          returnedHeaders.forEach((header) => {
+            allHeaders[header.key] = header.value;
+          });
+
+          options.headers = allHeaders;
+        }
+      }
     }
 
     if (typeof options.historyApiFallback === "undefined") {
diff --git a/test/e2e/__snapshots__/headers.test.js.snap.webpack4 b/test/e2e/__snapshots__/headers.test.js.snap.webpack4
index c9edf9f641..2deab3832d 100644
--- a/test/e2e/__snapshots__/headers.test.js.snap.webpack4
+++ b/test/e2e/__snapshots__/headers.test.js.snap.webpack4
@@ -1,5 +1,15 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`headers option as a function returning an array should handle GET request with headers: console messages 1`] = `Array []`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: page errors 1`] = `Array []`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: response headers x-bar 1`] = `"value2"`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: response headers x-foo 1`] = `"value1"`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: response status 1`] = `200`;
+
 exports[`headers option as a function should handle GET request with headers as a function: console messages 1`] = `Array []`;
 
 exports[`headers option as a function should handle GET request with headers as a function: page errors 1`] = `Array []`;
diff --git a/test/e2e/__snapshots__/headers.test.js.snap.webpack5 b/test/e2e/__snapshots__/headers.test.js.snap.webpack5
index c9edf9f641..2deab3832d 100644
--- a/test/e2e/__snapshots__/headers.test.js.snap.webpack5
+++ b/test/e2e/__snapshots__/headers.test.js.snap.webpack5
@@ -1,5 +1,15 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`headers option as a function returning an array should handle GET request with headers: console messages 1`] = `Array []`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: page errors 1`] = `Array []`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: response headers x-bar 1`] = `"value2"`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: response headers x-foo 1`] = `"value1"`;
+
+exports[`headers option as a function returning an array should handle GET request with headers: response status 1`] = `200`;
+
 exports[`headers option as a function should handle GET request with headers as a function: console messages 1`] = `Array []`;
 
 exports[`headers option as a function should handle GET request with headers as a function: page errors 1`] = `Array []`;
diff --git a/test/e2e/headers.test.js b/test/e2e/headers.test.js
index 780c20d88d..8c1b216cdb 100644
--- a/test/e2e/headers.test.js
+++ b/test/e2e/headers.test.js
@@ -258,6 +258,78 @@ describe("headers option", () => {
     });
   });
 
+  describe("as a function returning an array", () => {
+    let compiler;
+    let server;
+    let page;
+    let browser;
+    let pageErrors;
+    let consoleMessages;
+
+    beforeEach(async () => {
+      compiler = webpack(config);
+
+      server = new Server(
+        {
+          headers: () => [
+            {
+              key: "X-Foo",
+              value: "value1",
+            },
+            {
+              key: "X-Bar",
+              value: "value2",
+            },
+          ],
+          port,
+        },
+        compiler
+      );
+
+      await server.start();
+
+      ({ page, browser } = await runBrowser());
+
+      pageErrors = [];
+      consoleMessages = [];
+    });
+
+    afterEach(async () => {
+      await browser.close();
+      await server.stop();
+    });
+
+    it("should handle GET request with headers", async () => {
+      page
+        .on("console", (message) => {
+          consoleMessages.push(message);
+        })
+        .on("pageerror", (error) => {
+          pageErrors.push(error);
+        });
+
+      const response = await page.goto(`http://127.0.0.1:${port}/main.js`, {
+        waitUntil: "networkidle0",
+      });
+
+      expect(response.headers()["x-foo"]).toMatchSnapshot(
+        "response headers x-foo"
+      );
+
+      expect(response.headers()["x-bar"]).toMatchSnapshot(
+        "response headers x-bar"
+      );
+
+      expect(response.status()).toMatchSnapshot("response status");
+
+      expect(consoleMessages.map((message) => message.text())).toMatchSnapshot(
+        "console messages"
+      );
+
+      expect(pageErrors).toMatchSnapshot("page errors");
+    });
+  });
+
   describe("dev middleware headers take precedence for dev middleware output files", () => {
     let compiler;
     let server;

From cde531941217ea5bce479f4d52e12d8efbae2508 Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Thu, 16 Sep 2021 08:36:31 +0530
Subject: [PATCH 7/8] refactor: code

---
 lib/Server.js | 39 +++++++++++++--------------------------
 1 file changed, 13 insertions(+), 26 deletions(-)

diff --git a/lib/Server.js b/lib/Server.js
index 7688da5dfc..6e407a55da 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -490,29 +490,7 @@ class Server {
       options.devMiddleware = {};
     }
 
-    // normalize `headers`
-    if (typeof options.headers !== "undefined") {
-      const allHeaders = {};
-
-      if (Array.isArray(options.headers)) {
-        options.headers.forEach((header) => {
-          allHeaders[header.key] = header.value;
-        });
-        options.headers = allHeaders;
-      }
-
-      if (typeof options.headers === "function") {
-        const returnedHeaders = options.headers();
-
-        if (Array.isArray(returnedHeaders)) {
-          returnedHeaders.forEach((header) => {
-            allHeaders[header.key] = header.value;
-          });
-
-          options.headers = allHeaders;
-        }
-      }
-    }
+    // No need to normalize `headers`
 
     if (typeof options.historyApiFallback === "undefined") {
       options.historyApiFallback = false;
@@ -1867,10 +1845,19 @@ class Server {
         headers = headers(req, res, this.middleware.context);
       }
 
-      // eslint-disable-next-line guard-for-in
-      for (const name in headers) {
-        res.setHeader(name, headers[name]);
+      const allHeaders = [];
+
+      if (typeof headers === "object" && !Array.isArray(headers)) {
+        // eslint-disable-next-line guard-for-in
+        for (const name in headers) {
+          allHeaders.push({ key: name, value: headers[name] });
+        }
+        headers = allHeaders;
       }
+
+      headers.forEach((header) => {
+        res.setHeader(header.key, header.value);
+      });
     }
 
     next();

From f2a2d9c3f3cb3d6b249e5bee0ac2c0d4761f17da Mon Sep 17 00:00:00 2001
From: Nitin Kumar <snitin315@gmail.com>
Date: Thu, 16 Sep 2021 16:53:55 +0530
Subject: [PATCH 8/8] refactor: code

Co-authored-by: Alexander Akait <4567934+alexander-akait@users.noreply.github.com>
---
 lib/Server.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Server.js b/lib/Server.js
index 6e407a55da..8193582d8f 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -1847,7 +1847,7 @@ class Server {
 
       const allHeaders = [];
 
-      if (typeof headers === "object" && !Array.isArray(headers)) {
+      if (!Array.isArray(headers)) {
         // eslint-disable-next-line guard-for-in
         for (const name in headers) {
           allHeaders.push({ key: name, value: headers[name] });