From 7322e3894f42acca9b6eef97b957e97401749853 Mon Sep 17 00:00:00 2001
From: feugy <damien@vercel.com>
Date: Fri, 25 Nov 2022 11:15:36 +0100
Subject: [PATCH] refactor(utils): extract enrichFromResponse() in a file

---
 packages/utils/src/edge-to-node/handler.ts  | 44 +++------------------
 packages/utils/src/edge-to-node/headers.ts  |  4 +-
 packages/utils/src/edge-to-node/index.ts    |  1 +
 packages/utils/src/edge-to-node/response.ts | 40 +++++++++++++++++++
 packages/utils/src/types.ts                 |  1 +
 5 files changed, 49 insertions(+), 41 deletions(-)
 create mode 100644 packages/utils/src/edge-to-node/response.ts

diff --git a/packages/utils/src/edge-to-node/handler.ts b/packages/utils/src/edge-to-node/handler.ts
index 7f86edeb3..0500cced4 100644
--- a/packages/utils/src/edge-to-node/handler.ts
+++ b/packages/utils/src/edge-to-node/handler.ts
@@ -1,52 +1,18 @@
-import type { IncomingMessage, ServerResponse } from 'http'
+import type { IncomingMessage, ServerResponse } from 'node:http'
 import type { WebHandler, NodeHandler } from '../types'
-import { transformToOugoingHeaders } from './headers'
-import { transformToReadable } from './stream'
+import { enrichFromResponse } from './response'
 
 export function transformToNode(webHandler: WebHandler): NodeHandler {
   return (request: IncomingMessage, response: ServerResponse) => {
     // TODO map incoming message
     // @ts-ignore TODO map IncompingMessage into Request
     const maybePromise = webHandler(request)
-    const mapResponse = buildResponseMapper(response)
     if (maybePromise instanceof Promise) {
-      maybePromise.then(mapResponse)
-    } else {
-      mapResponse(maybePromise)
-    }
-  }
-}
-
-function buildResponseMapper(serverResponse: ServerResponse) {
-  return function (webResponse: Response | null | undefined) {
-    if (!webResponse) {
-      serverResponse.end()
-      return
-    }
-    for (const [name, value] of Object.entries(
-      transformToOugoingHeaders(
-        // @ts-ignore getAll() may not be defined on headers object
-        webResponse.headers,
-        serverResponse.getHeaders()
+      maybePromise.then((webResponse) =>
+        enrichFromResponse(response, webResponse)
       )
-    )) {
-      serverResponse.setHeader(name, value)
-    }
-
-    serverResponse.statusCode = webResponse.status
-    serverResponse.statusMessage = webResponse.statusText
-    // TODO trailers? https://nodejs.org/api/http.html#responseaddtrailersheaders https://developer.mozilla.org/en-US/docs/Web/API/Response
-    if (!webResponse.body) {
-      serverResponse.end()
-      return
-    }
-    if ('getReader' in webResponse.body) {
-      transformToReadable(webResponse.body).pipe(serverResponse)
-    } else if ('pipe' in webResponse.body) {
-      // @ts-ignore TODO @shniz how could the web response body have a pipe operator?
-      webResponse.body.pipe(serverResponse)
     } else {
-      serverResponse.end(webResponse.body)
+      enrichFromResponse(response, maybePromise)
     }
   }
 }
diff --git a/packages/utils/src/edge-to-node/headers.ts b/packages/utils/src/edge-to-node/headers.ts
index dfd927e83..744b7c12e 100644
--- a/packages/utils/src/edge-to-node/headers.ts
+++ b/packages/utils/src/edge-to-node/headers.ts
@@ -1,9 +1,9 @@
 import type { Headers } from '@edge-runtime/primitives'
-import type { OutgoingHttpHeader } from 'node:http'
+import type { OutgoingHttpHeaders } from 'node:http'
 
 export function transformToOugoingHeaders(
   headers: Headers,
-  existingHeaders: Record<string, OutgoingHttpHeader> = {}
+  existingHeaders: OutgoingHttpHeaders = {}
 ) {
   for (const name of 'raw' in headers
     ? // @ts-ignore TODO @schniz where does raw come from?
diff --git a/packages/utils/src/edge-to-node/index.ts b/packages/utils/src/edge-to-node/index.ts
index 206e3c59f..155841678 100644
--- a/packages/utils/src/edge-to-node/index.ts
+++ b/packages/utils/src/edge-to-node/index.ts
@@ -1,3 +1,4 @@
 export * from './handler'
 export * from './headers'
+export * from './response'
 export * from './stream'
diff --git a/packages/utils/src/edge-to-node/response.ts b/packages/utils/src/edge-to-node/response.ts
new file mode 100644
index 000000000..d51983051
--- /dev/null
+++ b/packages/utils/src/edge-to-node/response.ts
@@ -0,0 +1,40 @@
+import { Response } from '@edge-runtime/primitives'
+import { ServerResponse } from 'node:http'
+import { transformToOugoingHeaders } from './headers'
+import { transformToReadable } from './stream'
+
+export function enrichFromResponse(
+  serverResponse: ServerResponse,
+  webResponse: Response | null | undefined
+) {
+  if (!webResponse) {
+    serverResponse.end()
+    return
+  }
+  for (const [name, value] of Object.entries(
+    transformToOugoingHeaders(
+      // @ts-ignore getAll() may not be defined on headers object
+      webResponse.headers,
+      serverResponse.getHeaders()
+    )
+  )) {
+    if (value !== undefined) {
+      serverResponse.setHeader(name, value)
+    }
+  }
+
+  serverResponse.statusCode = webResponse.status
+  serverResponse.statusMessage = webResponse.statusText
+  if (!webResponse.body) {
+    serverResponse.end()
+    return
+  }
+  if ('getReader' in webResponse.body) {
+    transformToReadable(webResponse.body).pipe(serverResponse)
+  } else if ('pipe' in webResponse.body) {
+    // @ts-ignore TODO @shniz how could the web response body have a pipe operator?
+    webResponse.body.pipe(serverResponse)
+  } else {
+    serverResponse.end(webResponse.body)
+  }
+}
diff --git a/packages/utils/src/types.ts b/packages/utils/src/types.ts
index 1a014faee..32409cc0c 100644
--- a/packages/utils/src/types.ts
+++ b/packages/utils/src/types.ts
@@ -1,4 +1,5 @@
 import type { IncomingMessage, ServerResponse } from 'http'
+import type { Request, Response } from '@edge-runtime/primitives'
 
 export type NodeHandler = (req: IncomingMessage, res: ServerResponse) => void
 export type WebHandler = (