Enable multiple headers with same name

Author: blakeembrey

package.json

@@ -8,7 +8,7 @@
     "dist/"
   ],
   "scripts": {
-    "lint": "tslint \"src/**/*.ts\"",
+    "lint": "tslint \"src/**/*.ts\" --type-check --project tsconfig.json",
     "build": "rimraf dist && tsc",
     "specs": "jest --coverage",
     "test": "npm run -s lint && npm run -s build && npm run -s specs",
@@ -39,12 +39,13 @@
   "devDependencies": {
     "jest": "^19.0.0",
     "rimraf": "^2.5.4",
-    "tslint": "^5.0.0",
-    "tslint-config-standard": "^4.0.0",
+    "tslint": "^5.1.0",
+    "tslint-config-standard": "^5.0.2",
     "typescript": "^2.2.1",
     "typings": "^2.1.0"
   },
   "dependencies": {
+    "bit-string-mask": "^1.0.0",
     "servie": "^0.2.0",
     "servie-errorhandler": "^0.1.0",
     "servie-finalhandler": "^0.1.0"

src/index.spec.ts

@@ -77,6 +77,35 @@ describe('servie-lambda', () => {
     })
   })
 
+  it('should support multiple headers of the same key', (done) => {
+    const handler = createHandler(() => {
+      return new Response({
+        headers: {
+          'Set-Cookie': ['a=a', 'b=b', 'c=c']
+        }
+      })
+    })
+
+    return handler(event, context, (err: Error | null, res: Result) => {
+      if (err) {
+        return done(err)
+      }
+
+      expect(res).toEqual({
+        statusCode: undefined,
+        body: undefined,
+        headers: {
+          'set-cookie': 'a=a',
+          'Set-cookie': 'b=b',
+          'sEt-cookie': 'c=c'
+        },
+        isBase64Encoded: false
+      })
+
+      return done()
+    })
+  })
+
   it('should log and rewrite errors', (done) => {
     const logError = jest.fn()
     const handler = createHandler(() => Promise.reject(new Error('boom')), { logError })

src/index.ts

@@ -1,9 +1,10 @@
 import { format } from 'url'
-import { Request, Response } from 'servie'
+import { Request, Response, Headers } from 'servie'
 import { errorhandler } from 'servie-errorhandler'
 import { finalhandler } from 'servie-finalhandler'
+import { mask } from 'bit-string-mask'
 
-export type App = (req: Request, next: () => Promise<Response>) => Promise<Response>
+export type App = (req: Request, next: () => Promise<Response>) => Response | Promise<Response>
 
 /**
  * AWS Lambda event object.
@@ -104,14 +105,14 @@ export function createHandler (fn: App, options: Options = {}) {
 
           returned = true
 
-          // Mark the response as finished when buffering is done.
+          // Mark the response as finished when buffering is complete.
           res.finished = true
           res.bytesTransferred = body ? body.length : 0
 
           return cb(null, {
             statusCode: res.status,
             body: body ? (isBase64Encoded ? body.toString('base64') : body.toString('utf8')) : undefined,
-            headers: res.headers.object(),
+            headers: getHeaders(res.headers),
             isBase64Encoded
           })
         })
@@ -134,3 +135,28 @@ export function createHandler (fn: App, options: Options = {}) {
       )
   }
 }
+
+/**
+ * Return a lambda compatible object of headers.
+ */
+function getHeaders (headers: Headers) {
+  const result = Object.create(null)
+
+  if (headers.raw.length) {
+    const obj = headers.object()
+
+    for (const key of Object.keys(obj)) {
+      const val = obj[key]
+
+      if (Array.isArray(val)) {
+        for (let i = 0; i < val.length; i++) {
+          result[mask(key, i)] = val[i]
+        }
+      } else {
+        result[key] = val
+      }
+    }
+  }
+
+  return result
+}

tsconfig.json

@@ -9,6 +9,8 @@
     "module": "commonjs",
     "moduleResolution": "node",
     "declaration": true,
+    "alwaysStrict": true,
+    "strictNullChecks": true,
     "noImplicitAny": true,
     "noImplicitThis": true,
     "noImplicitReturns": true,