Adds option to disable helpers

Author: ctrlplusb

.vscode/settings.json

@@ -1,3 +1,4 @@
 {
-    "editor.tabSize": 2
+    "editor.tabSize": 2,
+    "typescript.tsdk": "node_modules/typescript/lib"
 }

src/__tests__/vercel-node-server.test.ts

@@ -1,5 +1,5 @@
 import { NowRequest, NowResponse } from '@vercel/node';
-import { Server } from 'http';
+import { Server, IncomingMessage, ServerResponse } from 'http';
 import axios from 'axios';
 import fs from 'fs';
 import path from 'path';
@@ -298,3 +298,51 @@ describe('request handling', () => {
     });
   });
 });
+
+describe('disableHelpers', () => {
+  let simpleServer: Server;
+  let simpleServerUrl: string;
+  let route: (req: IncomingMessage, res: ServerResponse) => void;
+
+  beforeAll(async () => {
+    simpleServer = createServer(
+      (req, res) => {
+        if (route) {
+          return route(req, res);
+        }
+      },
+      { disableHelpers: true }
+    );
+    simpleServerUrl = await listen(simpleServer);
+  });
+
+  afterAll(() => {
+    simpleServer.close();
+  });
+
+  it('does not apply the vercel helpers', async () => {
+    // ARRANGE
+    let actualRequest: any;
+    let actualResponse: any;
+    route = (req, res) => {
+      actualRequest = req;
+      actualResponse = res;
+      res.end();
+    };
+
+    // ACT
+    await axios.get(`${simpleServerUrl}?one=item1&two=item2`, {
+      headers: {
+        Cookie: 'foo=bar',
+      },
+    });
+
+    // ASSERT
+    expect(actualRequest.query).toBeUndefined();
+    expect(actualRequest.body).toBeUndefined();
+    expect(actualRequest.cookies).toBeUndefined();
+    expect(actualResponse.status).toBeUndefined();
+    expect(actualResponse.json).toBeUndefined();
+    expect(actualResponse.send).toBeUndefined();
+  });
+});

src/index.ts

@@ -5,7 +5,7 @@ import {
   NowRequest,
   NowResponse,
 } from '@vercel/node';
-import { IncomingMessage, ServerResponse } from 'http';
+import { IncomingMessage, ServerResponse, Server, RequestListener } from 'http';
 import { parse } from 'cookie';
 import { parse as parseContentType } from 'content-type';
 import { parse as parseQS } from 'querystring';
@@ -109,11 +109,32 @@ export const enhanceResponse = (res: ServerResponse): NowResponse => {
   return nowRes;
 };
 
-export const createServer = (
-  route: (req: NowRequest, res: NowResponse) => any | Promise<any>
-) =>
-  micro(async (req: IncomingMessage, res: ServerResponse) => {
-    const nowReq = await enhanceRequest(req);
-    const nowRes = enhanceResponse(res);
-    return await route(nowReq, nowRes);
-  });
+export interface Config {
+  disableHelpers?: boolean;
+}
+
+interface DefaultConfig {
+  disableHelpers: false;
+}
+
+type NowRoute = (req: NowRequest, res: NowResponse) => void;
+
+export const createServer = <C extends Config = DefaultConfig>(
+  route: C extends undefined
+    ? NowRoute
+    : C['disableHelpers'] extends true
+    ? RequestListener
+    : NowRoute,
+  config?: C
+) => {
+  if (config != null && config.disableHelpers) {
+    // @ts-expect-error
+    return new Server(route);
+  } else {
+    return micro(async (req: IncomingMessage, res: ServerResponse) => {
+      const nowReq = await enhanceRequest(req);
+      const nowRes = enhanceResponse(res);
+      return await route(nowReq, nowRes);
+    });
+  }
+};