test: add test case

deps.ts

@@ -35,16 +35,3 @@ export function mergeHeaders(left: Headers, right: Headers): Headers {
 
   return left;
 }
-
-export function createResponse(
-  response: Response,
-  init?: ResponseInit,
-): Response {
-  const { body, headers, status, statusText } = response;
-
-  return new Response(body, {
-    headers: init?.headers ?? headers,
-    status: init?.status ?? status,
-    statusText: init?.statusText ?? statusText,
-  });
-}

middleware.ts

@@ -4,7 +4,6 @@
 import {
   append,
   CORSHeader,
-  createResponse,
   type Handler,
   isNumber,
   isString,
@@ -16,6 +15,7 @@ import {
 import {
   assertNonNegativeInteger,
   assertTokenFormat,
+  fromResponse,
   isCORSPreflightRequest,
   isCORSRequest,
   match,
@@ -41,6 +41,7 @@ export interface CORSHeaders {
   readonly exposeHeaders?: readonly string[];
 }
 
+/** Headers for CORS preflight request. */
 export interface CORSPreflightHeaders
   extends Omit<CORSHeaders, "exposeHeaders"> {
   /** `Access-Control-Allow-Methods`.
@@ -100,13 +101,6 @@ export function cors(options: CORSHeaders = {}): Middleware {
   });
 }
 
-function createOriginMatcher(
-  allowOrigins: readonly (string | RegExp)[],
-): (origin: string) => boolean {
-  return (origin: string) =>
-    allowOrigins.some((pattern) => match(origin, pattern));
-}
-
 /**
  * @internal
  */
@@ -127,7 +121,7 @@ export async function _cors(
     new Headers({ [Header.Vary]: finalVary }),
   );
 
-  if (!isCORSRequest(request)) return createResponse(response, { headers });
+  if (!isCORSRequest(request)) return fromResponse(response, { headers });
 
   const { matchOrigin, allowCredentials, exposeHeaders } = context;
   const origin = request.headers.get(Header.Origin);
@@ -147,9 +141,10 @@ export async function _cors(
 
   const finalHeaders = mergeHeaders(left, headers);
 
-  return createResponse(response, { headers: finalHeaders });
+  return fromResponse(response, { headers: finalHeaders });
 }
 
+/** Preflight middleware options. */
 export interface PreflightOptions extends CORSPreflightHeaders {
   /** Preflight response status code.
    * @default 204
@@ -257,7 +252,7 @@ export async function _preflight(
       new Headers({ [Header.Vary]: finalVary }),
     );
 
-    return createResponse(response, { headers });
+    return fromResponse(response, { headers });
   }
 
   const {
@@ -336,3 +331,10 @@ function createAssertTokens(subject: string, expected: string) {
     );
   };
 }
+
+function createOriginMatcher(
+  allowOrigins: readonly (string | RegExp)[],
+): (origin: string) => boolean {
+  return (origin: string) =>
+    allowOrigins.some((pattern) => match(origin, pattern));
+}

utils.ts

@@ -58,3 +58,17 @@ export function assertNonNegativeInteger(
 ): asserts input {
   if (!isNonNegativeInteger(input)) throw Error(msg);
 }
+
+/** Create {@link Response} from response. */
+export function fromResponse(
+  response: Response,
+  init?: ResponseInit,
+): Response {
+  const { body, headers, status, statusText } = response;
+
+  return new Response(body, {
+    headers: init?.headers ?? headers,
+    status: init?.status ?? status,
+    statusText: init?.statusText ?? statusText,
+  });
+}

utils_test.ts

@@ -0,0 +1,48 @@
+import { fromResponse } from "./utils.ts";
+import { assert, describe, equalsResponse, it, Status } from "./_dev_deps.ts";
+
+describe("fromResponse", () => {
+  it("should return new response what change partial properties", async () => {
+    assert(
+      await equalsResponse(fromResponse(new Response()), new Response(), true),
+    );
+    assert(
+      await equalsResponse(
+        fromResponse(new Response(null, { status: Status.NoContent })),
+        new Response(null, { status: Status.NoContent }),
+        true,
+      ),
+    );
+    assert(
+      await equalsResponse(
+        fromResponse(new Response(null, { status: Status.NoContent }), {
+          status: Status.OK,
+        }),
+        new Response(null, { status: Status.OK }),
+        true,
+      ),
+    );
+    assert(
+      await equalsResponse(
+        fromResponse(
+          new Response("test", {
+            headers: { "x-test": "test" },
+          }),
+          {
+            headers: {
+              "content-type": "text/plain",
+              "x-test2": "test",
+            },
+          },
+        ),
+        new Response("test", {
+          headers: {
+            "content-type": "text/plain",
+            "x-test2": "test",
+          },
+        }),
+        true,
+      ),
+    );
+  });
+});