Gatsby by default will transform Object.assign

This is done to support older browsers. Fixes #264

.babelrc

@@ -1,6 +1,4 @@
 {
   "presets": ['react', 'es2015', 'stage-0'],
-  "plugins": [
-    'transform-object-rest-spread'
-  ]
+  "plugins": []
 }

lib/utils/babel-config.js

@@ -2,12 +2,12 @@ import resolve from 'babel-core/lib/helpers/resolve'
 import fs from 'fs'
 import path from 'path'
 import json5 from 'json5'
-import startsWith from 'lodash/startswith'
+import startsWith from 'lodash/startsWith'
 import invariant from 'invariant'
 
 const DEFAULT_BABEL_CONFIG = {
   presets: ['react', 'es2015', 'stage-0'],
-  plugins: ['add-module-exports'],
+  plugins: ['add-module-exports', 'transform-object-assign'],
 }
 
 /**

package.json

@@ -14,6 +14,7 @@
     "babel-core": "^6.8.0",
     "babel-loader": "^6.2.4",
     "babel-plugin-add-module-exports": "^0.2.0",
+    "babel-plugin-transform-object-assign": "^6.8.0",
     "babel-preset-es2015": "^6.6.0",
     "babel-preset-react": "^6.5.0",
     "babel-preset-react-hmre": "^1.1.1",

test/fixtures/site-with-valid-babelrc/.babelrc

@@ -1,6 +1,3 @@
 {
-  "presets": ['react', 'es2015', 'stage-0'],
-  "plugins": [
-    'transform-object-rest-spread'
-  ]
+  "presets": ['react', 'es2015', 'stage-0']
 }

test/utils/babel-config.js

@@ -30,7 +30,6 @@ test('fixture can resolve plugins in gatsby directory (crawling up)', t => {
 
   const config = babelConfig(program)
   t.truthy(config.presets.length)
-  t.truthy(config.plugins.length)
 })
 
 test('throws error when babelrc is not parseable', t => {