fix: amend header serialization algorithm (#1523)

I needed to update very old [email protected] to [email protected]
which uses 2.x branch of node-fetch instead of 1.x branch.
[email protected] is no longer compatible with fetch API in browsers
and is incompatible with the fetch specification.

Ref #1508

Author: char0n

package-lock.json

@@ -101,7 +101,7 @@
     "btoa": "1.1.2",
     "buffer": "^5.1.0",
     "cookie": "^0.3.1",
-    "cross-fetch": "0.0.8",
+    "cross-fetch": "^3.0.4",
     "deep-extend": "^0.5.1",
     "encode-3986": "^1.0.0",
     "fast-json-patch": "~2.1.0",
@@ -121,9 +121,13 @@
       "**/test/*.js?(x)",
       "**/test/**/*.js?(x)"
     ],
+    "setupFilesAfterEnv": [
+      "<rootDir>/test/jest.setup.js"
+    ],
     "testPathIgnorePatterns": [
       "<rootDir>/node_modules/",
       "<rootDir>/test/data/",
+      "<rootDir>/test/jest.setup.js",
       "<rootDir>/test/specmap/data/",
       "<rootDir>/test/webpack-bundle/.tmp/"
     ]

package.json

@@ -2,6 +2,7 @@ import 'cross-fetch/polyfill' /* global fetch */
 import qs from 'qs'
 import jsYaml from 'js-yaml'
 import isString from 'lodash/isString'
+import isFunction from 'lodash/isFunction'
 
 // For testing
 export const self = {
@@ -104,7 +105,6 @@ export function serializeRes(oriRes, url, {loadSpec = false} = {}) {
   const contentType = res.headers['content-type']
   const useText = loadSpec || shouldDownloadAsText(contentType)
 
-  // Note: Response.blob not implemented in node-fetch 1.  Use buffer instead.
   const getBody = useText ? oriRes.text : (oriRes.blob || oriRes.buffer)
 
   return getBody.call(oriRes).then((body) => {
@@ -125,29 +125,26 @@ export function serializeRes(oriRes, url, {loadSpec = false} = {}) {
   })
 }
 
+function serializeHeaderValue(value) {
+  const isMulti = value.includes(', ')
+
+  return isMulti ? value.split(', ') : value
+}
+
 // Serialize headers into a hash, where mutliple-headers result in an array.
 //
 // eg: Cookie: one
 //     Cookie: two
 //  =  { Cookie: [ "one", "two" ]
 export function serializeHeaders(headers = {}) {
-  const obj = {}
-
-  // Iterate over headers, making multiple-headers into an array
-  if (typeof headers.forEach === 'function') {
-    headers.forEach((headerValue, header) => {
-      if (obj[header] !== undefined) {
-        obj[header] = Array.isArray(obj[header]) ? obj[header] : [obj[header]]
-        obj[header].push(headerValue)
-      }
-      else {
-        obj[header] = headerValue
-      }
-    })
-    return obj
-  }
-
-  return obj
+  if (!isFunction(headers.entries)) return {}
+
+  return Array
+    .from(headers.entries())
+    .reduce((acc, [header, value]) => {
+      acc[header] = serializeHeaderValue(value)
+      return acc
+    }, {})
 }
 
 export function isFile(obj, navigatorObj) {

src/http.js

@@ -310,9 +310,8 @@ describe('http', () => {
       expect(encodeFormOrQuery(req.query)).toEqual('id=1,2')
     })
 
-    test('should handle custom array serilization', () => {
-      // Given
-      fetchMock.get('*', {hello: 'world'})
+    test('should handle custom array serialization', () => {
+      fetchMock.get('*', {body: 'response body'})
       const req = {
         url: 'http://example.com',
         method: 'GET',
@@ -336,6 +335,9 @@ describe('http', () => {
       // Given
       fetchMock.get('*', (url, opts) => {
         return {
+          headers: {
+            'Content-Type': 'text/plain',
+          },
           body: opts.headers.WilliamCWilliamsHeader
         }
       })
@@ -360,23 +362,32 @@ describe('http', () => {
     test(
       'should serialize fetch-like response and call serializeHeaders',
       () => {
-        const headers = {
-          Authorization: ['Basic hoop-la', 'Advanced hoop-la']
-        }
-
-        const res = fetchMock.mock('http://swagger.io', {headers})
+        // cross-fetch exposes FetchAPI methods onto global
+        require('cross-fetch/polyfill')
+        const response = new Response('data', { // eslint-disable-line no-undef
+          status: 200,
+          headers: {
+            Authorization: 'Basic hoop-la, Advanced hoop-la',
+            'Content-Type': 'text/plain',
+          }
+        })
 
-        return fetch('http://swagger.io').then((_res) => { // eslint-disable-line no-undef
-          return serializeRes(_res, 'https://swagger.io')
-        }).then((resSerialize) => {
-          expect(resSerialize.headers).toEqual({authorization: ['Basic hoop-la', 'Advanced hoop-la']})
-        }).then(fetchMock.restore)
+        return serializeRes(response, 'https://swagger.io')
+          .then((serializedResponse) => {
+            expect(serializedResponse.headers).toEqual({
+              authorization: ['Basic hoop-la', 'Advanced hoop-la'],
+              'content-type': 'text/plain'
+            })
+          })
       }
     )
 
     test(
       'should set .text and .data to body Blob or Buffer for binary response',
       () => {
+        // cross-fetch exposes FetchAPI methods onto global
+        require('cross-fetch/polyfill')
+
         const headers = {
           'Content-Type': 'application/octet-stream'
         }
@@ -392,11 +403,11 @@ describe('http', () => {
         }).then((resSerialize) => {
           expect(resSerialize.data).toBe(resSerialize.text)
           if (originalRes.blob) {
-            expect(resSerialize.data).toBeInstanceOf(Blob) // eslint-disable-line no-undef
+            expect(Object.prototype.toString.call(resSerialize.data)).toBe('[object Blob]')
           }
           else {
             expect(resSerialize.data).toBeInstanceOf(Buffer)
-            expect(resSerialize.data).toEqual(new Buffer(body))
+            expect(resSerialize.data).toEqual(Buffer.from(body))
           }
         }).then(fetchMock.restore)
       }
@@ -409,7 +420,7 @@ describe('http', () => {
           'Content-Type': 'application/json'
         }
 
-        const body = 'body data'
+        const body = '{}'
         const res = fetchMock.mock('http://swagger.io', {body, headers})
 
         return fetch('http://swagger.io').then((_res) => { // eslint-disable-line no-undef

test/http.js

@@ -0,0 +1,9 @@
+import fetchMock from 'fetch-mock'
+import {Headers, Request, Response} from 'cross-fetch'
+
+fetchMock.setImplementations({
+  Promise,
+  Request,
+  Response,
+  Headers
+})