Add a file upload method that uses XMLHttpRequest

src/actions/fileUpload.js

 import request from '../helpers/api'
+import endpoint from '../helpers/endpoint'
+import token from '../helpers/token'
 import * as T from './types'
 
 function fileUploadRequest () {
@@ -49,3 +51,35 @@ export function fileUpload (file) {
       )
   }
 }
+
+export function fileUploadXHR (file) {
+  return (dispatch) => {
+    dispatch(fileUploadRequest())
+
+    const data = new FormData()
+    data.append('file', file)
+
+    const request = new XMLHttpRequest()
+    request.open('POST', endpoint + '/upload')
+    request.setRequestHeader('Authorization', 'Bearer ' + token())
+    request.setRequestHeader('Accept', 'text/plain') // the response is a URL
+    request.send(data)
+
+    request.addEventListener('load', event => {
+      if (request.status === 200) {
+        // response success
+        dispatch(fileUploadSuccess(file))
+      } else {
+        // response error
+        dispatch(fileUploadFailure('There was an error uploading the file'))
+      }
+    })
+
+    // network error
+    request.addEventListener('error', event => {
+      dispatch(fileUploadFailure('There was an error uploading the file'))
+    })
+
+    return request
+  }
+}

src/helpers/api.js

 import fetch from 'isomorphic-fetch'
-
-const API_ENDPOINT = CONFIG['pubsweet-server'].API_ENDPOINT
+import endpoint from './endpoint'
 
 // read the authentication token from LocalStorage
 import getToken from './token'
@@ -24,7 +23,7 @@ const request = (url, options = {}) => {
   }
 
   if (!url.match(/^https?:/)) {
-    url = API_ENDPOINT + url
+    url = endpoint() + url
   }
 
   return fetch(url, options).then(response => {

src/helpers/endpoint.js

+/* global CONFIG */
+
+module.exports = () => CONFIG['pubsweet-server'].API_ENDPOINT