Fix babel and eslint config [SCI-1461]

.babelrc

@@ -11,7 +11,8 @@
         "useBuiltIns": true
       }
     ],
-    "react"
+    "react",
+    "es2015"
   ],
   "plugins": [
     "syntax-dynamic-import",
@@ -21,5 +22,10 @@
         "spec": true
       }
     ]
-  ]
+  ],
+  "env": {
+    "test": {
+      "plugins": ["transform-es2015-modules-commonjs"]
+    }
+  }
 }

.eslintrc.json

@@ -1,9 +1,20 @@
 {
-  "extends": "google",
   "env": {
     "browser": true,
     "jquery": true
   },
+  "plugins": [
+    "react"
+  ],
+  "extends": ["eslint:recommended", "plugin:react/recommended"],
+  "parserOptions": {
+    "sourceType": "module",
+    "ecmaVersion": 6,
+    "ecmaFeatures": {
+      "impliedStrict": true,
+      "jsx": true
+    }
+  },
   "rules": {
     "spaced-comment": [
       "error",

app/javascript/packs/hello_react.jsx

@@ -21,6 +21,6 @@ Hello.propTypes = {
 document.addEventListener('DOMContentLoaded', () => {
   ReactDOM.render(
     <Hello name="React" />,
-    document.body.appendChild(document.createElement('div')),
+    document.body.appendChild(document.createElement('div'))
   )
 })

package.json

@@ -22,6 +22,7 @@
   "devDependencies": {
     "eslint": "^3.7.1",
     "eslint-config-google": "^0.5.0",
+    "eslint-plugin-react": "^7.1.0",
     "webpack-dev-server": "^2.5.1"
   },
   "dependencies": {