Handling case where options.headers is of type window.Headers

src/__test__/fetch-util.spec.js

@@ -0,0 +1,25 @@
+// @flow
+/* eslint-env jest */
+/* global Headers */
+
+import { copyHeaders } from '../fetch-util'
+
+describe('copyHeaders', () => {
+  it('returns an object', () => expect(copyHeaders({})).toEqual({}))
+  it('returns a copy of whatever is passed in as first param', () =>
+    expect(copyHeaders({ foo: 42 })).toEqual({ foo: 42 }))
+  it('handles option.headers as object', () =>
+    expect(copyHeaders({ foo: 42 }, { headers: { bar: 1337 } })).toEqual({
+      foo: 42,
+      bar: 1337
+    }))
+  xit('handles options.headers as Headers', () => {
+    // Enable this when there is support for window.Headers
+    const headers = new Headers()
+    headers.append('bar', '1337')
+    expect(copyHeaders({ foo: '42' }, { headers })).toEqual({
+      foo: '42',
+      bar: '1337'
+    })
+  })
+})

src/fetch-util.js

@@ -0,0 +1,17 @@
+export function copyHeaders(newHeaders, oldOptions = {}) {
+  return {
+    ...normalizeHeaders(oldOptions.headers),
+    ...normalizeHeaders(newHeaders)
+  }
+}
+
+function normalizeHeaders(headers = {}) {
+  if (!headers.forEach) {
+    return headers
+  }
+  const newHeaders = {}
+  headers.forEach((value, key) => {
+    newHeaders[key] = value
+  })
+  return newHeaders
+}

src/webid-oidc.js

@@ -9,6 +9,7 @@ import { currentUrl, navigateTo, toUrlString } from './url-util'
 import type { webIdOidcSession } from './session'
 import type { AsyncStorage } from './storage'
 import { defaultStorage, getData, updateStorage } from './storage'
+import { copyHeaders } from './fetch-util'
 
 export async function login(
   idp: string,
@@ -191,10 +192,12 @@ export async function fetchWithCredentials(
   const authenticatedOptions = {
     ...options,
     credentials: 'include',
-    headers: {
-      ...(options && options.headers ? options.headers : {}),
-      authorization: `Bearer ${popToken}`
-    }
+    headers: copyHeaders(
+      {
+        authorization: `Bearer ${popToken}`
+      },
+      options
+    )
   }
   return fetch(input, authenticatedOptions)
 }