feat: allow array for headers option

src/middleware.js

@@ -87,14 +87,20 @@ export default function wrapper(context) {
         headers = headers(req, res, context);
       }
 
-      if (headers) {
-        const names = Object.keys(headers);
+      const allHeaders = [];
 
-        for (const name of names) {
-          setHeaderForResponse(res, name, headers[name]);
+      if (!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) => {
+        setHeaderForResponse(res, header.key, header.value);
+      });
+
       if (!getHeaderFromResponse(res, "Content-Type")) {
         // content-type name(like application/javascript; charset=utf-8) or false
         const contentType = mime.contentType(path.extname(filename));

src/options.json

@@ -29,6 +29,24 @@
     },
     "headers": {
       "anyOf": [
+        {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+              "key": {
+                "description": "key of header.",
+                "type": "string"
+              },
+              "value": {
+                "description": "value of header.",
+                "type": "string"
+              }
+            }
+          },
+          "minItems": 1
+        },
         {
           "type": "object"
         },

test/__snapshots__/validation-options.test.js.snap.webpack4

@@ -1,12 +1,25 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`validation should throw an error on the "headers" option with "[]" value 1`] = `
+"Invalid options object. Dev Middleware has been initialized using an options object that does not match the API schema.
+ - options.headers should be a non-empty array."
+`;
+
+exports[`validation should throw an error on the "headers" option with "[{"foo":"bar"}]" value 1`] = `
+"Invalid options object. Dev Middleware 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[`validation should throw an error on the "headers" option with "1" value 1`] = `
 "Invalid options object. Dev Middleware 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 pass custom HTTP headers on each request
    -> Read more at https://github.com/webpack/webpack-dev-middleware#headers
    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."
@@ -15,10 +28,12 @@ exports[`validation should throw an error on the "headers" option with "1" value
 exports[`validation should throw an error on the "headers" option with "true" value 1`] = `
 "Invalid options object. Dev Middleware 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 pass custom HTTP headers on each request
    -> Read more at https://github.com/webpack/webpack-dev-middleware#headers
    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."

test/__snapshots__/validation-options.test.js.snap.webpack5

@@ -1,12 +1,25 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`validation should throw an error on the "headers" option with "[]" value 1`] = `
+"Invalid options object. Dev Middleware has been initialized using an options object that does not match the API schema.
+ - options.headers should be a non-empty array."
+`;
+
+exports[`validation should throw an error on the "headers" option with "[{"foo":"bar"}]" value 1`] = `
+"Invalid options object. Dev Middleware 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[`validation should throw an error on the "headers" option with "1" value 1`] = `
 "Invalid options object. Dev Middleware 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 pass custom HTTP headers on each request
    -> Read more at https://github.com/webpack/webpack-dev-middleware#headers
    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."
@@ -15,10 +28,12 @@ exports[`validation should throw an error on the "headers" option with "1" value
 exports[`validation should throw an error on the "headers" option with "true" value 1`] = `
 "Invalid options object. Dev Middleware 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 pass custom HTTP headers on each request
    -> Read more at https://github.com/webpack/webpack-dev-middleware#headers
    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."

test/middleware.test.js

@@ -1012,6 +1012,7 @@ describe.each([
           instance = middleware(compiler);
 
           app = framework();
+          // eslint-disable-next-line no-shadow
           app.use((req, res, next) => {
             // Express API
             if (res.set) {
@@ -2133,6 +2134,7 @@ describe.each([
           app = framework();
           app.use(instance);
 
+          // eslint-disable-next-line no-shadow
           app.use("/file.jpg", (req, res) => {
             // Express API
             if (res.send) {
@@ -2762,6 +2764,7 @@ describe.each([
         });
 
         it('should return the "200" code for the "GET" request to path not in outputFileSystem but not return headers', async () => {
+          // eslint-disable-next-line no-shadow
           app.use("/file.jpg", (req, res) => {
             // Express API
             if (res.send) {
@@ -2779,6 +2782,62 @@ describe.each([
           expect(res.headers["X-nonsense-2"]).toBeUndefined();
         });
       });
+
+      describe("works with array of objects", () => {
+        beforeEach((done) => {
+          const compiler = getCompiler(webpackConfig);
+
+          instance = middleware(compiler, {
+            headers: [
+              {
+                key: "X-Foo",
+                value: "value1",
+              },
+              {
+                key: "X-Bar",
+                value: "value2",
+              },
+            ],
+          });
+
+          app = framework();
+          app.use(instance);
+
+          listen = listenShorthand(done);
+
+          req = request(app);
+        });
+
+        afterEach(close);
+
+        it('should return the "200" code for the "GET" request to the bundle file and return headers', async () => {
+          const response = await req.get(`/bundle.js`);
+
+          expect(response.statusCode).toEqual(200);
+          expect(response.headers["x-foo"]).toEqual("value1");
+          expect(response.headers["x-bar"]).toEqual("value2");
+        });
+
+        it('should return the "200" code for the "GET" request to path not in outputFileSystem but not return headers', async () => {
+          // eslint-disable-next-line no-shadow
+          app.use("/file.jpg", (req, res) => {
+            // Express API
+            if (res.send) {
+              res.send("welcome");
+            }
+            // Connect API
+            else {
+              res.end("welcome");
+            }
+          });
+
+          const res = await request(app).get("/file.jpg");
+          expect(res.statusCode).toEqual(200);
+          expect(res.headers["x-foo"]).toBeUndefined();
+          expect(res.headers["x-bar"]).toBeUndefined();
+        });
+      });
+
       describe("works with function", () => {
         beforeEach((done) => {
           const compiler = getCompiler(webpackConfig);
@@ -2808,6 +2867,7 @@ describe.each([
         });
 
         it('should return the "200" code for the "GET" request to path not in outputFileSystem but not return headers', async () => {
+          // eslint-disable-next-line no-shadow
           app.use("/file.jpg", (req, res) => {
             // Express API
             if (res.send) {
@@ -2826,12 +2886,67 @@ describe.each([
         });
       });
 
+      describe("works with function returning an array", () => {
+        beforeEach((done) => {
+          const compiler = getCompiler(webpackConfig);
+
+          instance = middleware(compiler, {
+            headers: () => [
+              {
+                key: "X-Foo",
+                value: "value1",
+              },
+              {
+                key: "X-Bar",
+                value: "value2",
+              },
+            ],
+          });
+
+          app = framework();
+          app.use(instance);
+
+          listen = listenShorthand(done);
+
+          req = request(app);
+        });
+
+        afterEach(close);
+
+        it('should return the "200" code for the "GET" request to the bundle file and return headers', async () => {
+          const response = await req.get(`/bundle.js`);
+
+          expect(response.statusCode).toEqual(200);
+          expect(response.headers["x-foo"]).toEqual("value1");
+          expect(response.headers["x-bar"]).toEqual("value2");
+        });
+
+        it('should return the "200" code for the "GET" request to path not in outputFileSystem but not return headers', async () => {
+          // eslint-disable-next-line no-shadow
+          app.use("/file.jpg", (req, res) => {
+            // Express API
+            if (res.send) {
+              res.send("welcome");
+            }
+            // Connect API
+            else {
+              res.end("welcome");
+            }
+          });
+
+          const res = await req.get("/file.jpg");
+          expect(res.statusCode).toEqual(200);
+          expect(res.headers["x-foo"]).toBeUndefined();
+          expect(res.headers["x-bar"]).toBeUndefined();
+        });
+      });
+
       describe("works with headers function with params", () => {
         beforeEach((done) => {
           const compiler = getCompiler(webpackConfig);
 
           instance = middleware(compiler, {
-            // eslint-disable-next-line no-unused-vars
+            // eslint-disable-next-line no-unused-vars, no-shadow
             headers: (req, res, context) => {
               res.setHeader("X-nonsense-1", "yes");
               res.setHeader("X-nonsense-2", "no");
@@ -2857,6 +2972,7 @@ describe.each([
         });
 
         it('should return the "200" code for the "GET" request to path not in outputFileSystem but not return headers', async () => {
+          // eslint-disable-next-line no-shadow
           app.use("/file.jpg", (req, res) => {
             // Express API
             if (res.send) {
@@ -2934,6 +3050,7 @@ describe.each([
 
         app = framework();
         app.use(instance);
+        // eslint-disable-next-line no-shadow
         app.use((req, res) => {
           // eslint-disable-next-line prefer-destructuring
           locals = res.locals;

test/validation-options.test.js

@@ -28,8 +28,12 @@ describe("validation", () => {
       failure: [{}, true],
     },
     headers: {
-      success: [{ "X-Custom-Header": "yes" }, () => {}],
-      failure: [true, 1],
+      success: [
+        { "X-Custom-Header": "yes" },
+        () => {},
+        [{ key: "foo", value: "bar" }],
+      ],
+      failure: [true, 1, [], [{ foo: "bar" }]],
     },
     publicPath: {
       success: ["/foo", "", "auto", () => "/public/path"],