fix headers object to accept duplicated keys like set-cookie

.vscode/settings.json

@@ -1 +1 @@
-{}
+{}

README.md

@@ -1,7 +1,6 @@
 [![JSR](https://jsr.io/badges/@deco/warp)](https://jsr.io/@deco/warp)
 [![JSR Score](https://jsr.io/badges/@deco/warp/score)](https://jsr.io/@deco/warp)
 
-
 # Warp
 
 **Warp** is a simple tool that allows your locally running HTTP(s) servers to

deno.json

@@ -1,6 +1,6 @@
 {
   "name": "@deco/warp",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "exports": "./mod.ts",
   "tasks": {
     "check": "deno fmt && deno lint && deno check mod.ts"

handlers.client.ts

@@ -220,13 +220,22 @@ async function doFetch(
         signal,
       },
     );
+
+    const headers: Record<string, Array<string>> = {};
+
+    for (const [key, value] of response.headers.entries()) {
+      headers[key] ??= [];
+      headers[key].push(value);
+    }
+
     await clientCh.send({
       type: "response-start",
       id: request.id,
       statusCode: response.status,
       statusMessage: response.statusText,
-      headers: Object.fromEntries(response.headers.entries()),
+      headers,
     });
+
     const body = response?.body;
     const stream = body ? makeChanStream(body) : undefined;
     for await (const chunk of stream?.recv(signal) ?? []) {

handlers.server.ts

@@ -35,9 +35,17 @@ const onResponseStart: ClientMessageHandler<ResponseStartMessage> = (
     return;
   }
   const headers = new Headers();
-  Object.entries(message.headers).forEach(([key, value]: [string, string]) => {
-    headers.set(key, value);
-  });
+  Object.entries(message.headers).forEach(
+    ([key, value]: [string, string | Array<string>]) => {
+      if (typeof value === "string") {
+        headers.set(key, value);
+      } else if (Array.isArray(value)) {
+        value.forEach((v) => {
+          headers.append(key, v);
+        });
+      }
+    },
+  );
   const shouldBeNullBody = NULL_BODIES.includes(message.statusCode);
   const stream = !shouldBeNullBody && request.responseBodyChan
     ? makeReadableStream(request.responseBodyChan)

messages.ts

@@ -19,7 +19,7 @@ export interface ResponseStartMessage {
   id: string;
   statusCode: number;
   statusMessage: string;
-  headers: Record<string, string>;
+  headers: Record<string, Array<string>>;
 }
 export interface DataMessage {
   type: "data";