fix: remove global window from Map() usage, update eslint rules for new es6 environment (jquense#1195)

Author: sedenardi

.eslintrc

@@ -2,7 +2,8 @@ parser: babel-eslint
 extends:
   - jason/react
   - prettier
-
+env:
+  es6: true
 rules:
   global-require: off
   no-unused-vars: [2, {

src/utils/Resources.js

@@ -10,7 +10,7 @@ export default function Resources(resources, accessors) {
     },
 
     groupEvents(events) {
-      const eventsByResource = new window.Map()
+      const eventsByResource = new Map()
 
       if (!resources) {
         // Return all events if resources are not provided