feat(response): set content-length header for empty response (#58)

.changeset/real-carpets-rhyme.md

@@ -0,0 +1,5 @@
+---
+"openapi-msw": minor
+---
+
+Added "content-length" header for `response(...).empty()`. If no "content-length" header is provided in the response init, the "content-length" header is now set with the value "0". See #56 for more details.

src/response.ts

@@ -91,9 +91,13 @@ export function createResponseHelper<
     };
 
     const empty: EmptyResponse<typeof status> = (init) => {
+      const headers = new Headers(init?.headers);
+      if (!headers.has("content-length")) headers.set("content-length", "0");
+
       return new HttpResponse(null, {
         status: status as number,
         ...init,
+        headers,
       }) as StrictResponse<null>;
     };
 

test/response-content.test.ts

@@ -88,6 +88,36 @@ describe("Given an OpenAPI schema endpoint with response content", () => {
     expect(result?.response?.status).toBe(204);
   });
 
+  test("When an empty response is created, Then the response includes a content-length header", async () => {
+    const request = new Request(new URL("/resource", "http://localhost:3000"), {
+      method: "get",
+    });
+
+    const handler = http.get("/resource", ({ response }) => {
+      return response(204).empty();
+    });
+    const result = await handler.run({ request });
+
+    expect(result?.response?.status).toBe(204);
+    expect(result?.response?.headers.has("content-length")).toBeTruthy();
+    expect(result?.response?.headers.get("content-length")).toBe("0");
+  });
+
+  test("When an empty response with content-length is created, Then the provided content-length header is used", async () => {
+    const request = new Request(new URL("/resource", "http://localhost:3000"), {
+      method: "get",
+    });
+
+    const handler = http.get("/resource", ({ response }) => {
+      return response(204).empty({ headers: { "content-length": "32" } });
+    });
+    const result = await handler.run({ request });
+
+    expect(result?.response?.status).toBe(204);
+    expect(result?.response?.headers.has("content-length")).toBeTruthy();
+    expect(result?.response?.headers.get("content-length")).toBe("32");
+  });
+
   test("When the response helper is used for wildcard status codes, Then a specific response status must be chosen", async () => {
     const request = new Request(new URL("/resource", "http://localhost:3000"), {
       method: "get",