Use the default babel-config from CRA.

dist/server/config/babel.js

@@ -1,12 +1,42 @@
 'use strict';
 
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
 module.exports = {
+  // Don't try to find .babelrc because we want to force this configuration.
   babelrc: false,
+  // This is a feature of `babel-loader` for webpack (not Babel itself).
+  // It enables caching results in OS temporary directory for faster rebuilds.
   cacheDirectory: true,
-  presets: ['babel-preset-es2015', 'babel-preset-es2016', 'babel-preset-stage-0', 'babel-preset-react'].map(require.resolve),
-  plugins: [].map(require.resolve).concat([[require.resolve('babel-plugin-transform-runtime'), {
+  presets: [
+  // let, const, destructuring, classes, modules
+  'babel-preset-es2015',
+  // exponentiation
+  'babel-preset-es2016',
+  // JSX, Flow
+  'babel-preset-react'],
+  plugins: [
+  // function x(a, b, c,) { }
+  'babel-plugin-syntax-trailing-function-commas',
+  // await fetch()
+  'babel-plugin-syntax-async-functions',
+  // class { handleClick = () => { } }
+  'babel-plugin-transform-class-properties',
+  // { ...todo, completed: true }
+  'babel-plugin-transform-object-rest-spread',
+  // function* () { yield 42; yield 43; }
+  'babel-plugin-transform-regenerator',
+  // Polyfills the runtime needed for async/await and generators
+  ['babel-plugin-transform-runtime', {
     helpers: false,
     polyfill: false,
     regenerator: true
-  }]])
+  }]]
 };

dist/server/config/babel.prod.js

@@ -1,11 +1,41 @@
 'use strict';
 
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
 module.exports = {
+  // Don't try to find .babelrc because we want to force this configuration.
   babelrc: false,
-  presets: ['babel-preset-es2015', 'babel-preset-es2016', 'babel-preset-stage-0', 'babel-preset-react'].map(require.resolve),
-  plugins: ['babel-plugin-transform-react-constant-elements'].map(require.resolve).concat([[require.resolve('babel-plugin-transform-runtime'), {
+  presets: [
+  // let, const, destructuring, classes, modules
+  'babel-preset-es2015',
+  // exponentiation
+  'babel-preset-es2016',
+  // JSX, Flow
+  'babel-preset-react'],
+  plugins: [
+  // function x(a, b, c,) { }
+  'babel-plugin-syntax-trailing-function-commas',
+  // await fetch()
+  'babel-plugin-syntax-async-functions',
+  // class { handleClick = () => { } }
+  'babel-plugin-transform-class-properties',
+  // { ...todo, completed: true }
+  'babel-plugin-transform-object-rest-spread',
+  // function* () { yield 42; yield 43; }
+  'babel-plugin-transform-regenerator',
+  // Polyfills the runtime needed for async/await and generators
+  ['babel-plugin-transform-runtime', {
     helpers: false,
     polyfill: false,
     regenerator: true
-  }]])
+  }],
+  // Optimization: hoist JSX that never changes out of render()
+  'babel-plugin-transform-react-constant-elements']
 };

package.json

@@ -33,10 +33,14 @@
     "babel-plugin-transform-react-constant-elements": "^6.9.1",
     "babel-plugin-transform-runtime": "^6.12.0",
     "babel-polyfill": "^6.9.1",
+    "babel-plugin-syntax-async-functions": "^6.8.0",
+    "babel-plugin-syntax-trailing-function-commas": "^6.8.0",
+    "babel-plugin-transform-class-properties": "^6.11.5",
+    "babel-plugin-transform-object-rest-spread": "^6.8.0",
+    "babel-plugin-transform-regenerator": "^6.11.4",
     "babel-preset-es2015": "^6.9.0",
     "babel-preset-es2016": "^6.11.3",
     "babel-preset-react": "^6.11.1",
-    "babel-preset-stage-0": "^6.5.0",
     "babel-runtime": "^6.9.2",
     "case-sensitive-paths-webpack-plugin": "^1.1.2",
     "cjson": "^0.4.0",
@@ -71,6 +75,7 @@
     "babel-cli": "^6.11.4",
     "babel-eslint": "^6.1.2",
     "babel-plugin-transform-runtime": "^6.9.0",
+    "babel-preset-stage-0": "^6.5.0",
     "chai": "^3.5.0",
     "deep-equal": "^1.0.1",
     "enzyme": "^2.2.0",

src/server/config/babel.js

@@ -1,17 +1,42 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
 module.exports = {
+  // Don't try to find .babelrc because we want to force this configuration.
   babelrc: false,
+  // This is a feature of `babel-loader` for webpack (not Babel itself).
+  // It enables caching results in OS temporary directory for faster rebuilds.
   cacheDirectory: true,
   presets: [
+    // let, const, destructuring, classes, modules
     'babel-preset-es2015',
+    // exponentiation
     'babel-preset-es2016',
-    'babel-preset-stage-0',
+    // JSX, Flow
     'babel-preset-react',
-  ].map(require.resolve),
-  plugins: [].map(require.resolve).concat([
-    [require.resolve('babel-plugin-transform-runtime'), {
+  ],
+  plugins: [
+    // function x(a, b, c,) { }
+    'babel-plugin-syntax-trailing-function-commas',
+    // await fetch()
+    'babel-plugin-syntax-async-functions',
+    // class { handleClick = () => { } }
+    'babel-plugin-transform-class-properties',
+    // { ...todo, completed: true }
+    'babel-plugin-transform-object-rest-spread',
+    // function* () { yield 42; yield 43; }
+    'babel-plugin-transform-regenerator',
+    // Polyfills the runtime needed for async/await and generators
+    ['babel-plugin-transform-runtime', {
       helpers: false,
       polyfill: false,
       regenerator: true,
     }],
-  ]),
+  ],
 };

src/server/config/babel.prod.js

@@ -1,18 +1,41 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
 module.exports = {
+  // Don't try to find .babelrc because we want to force this configuration.
   babelrc: false,
   presets: [
+    // let, const, destructuring, classes, modules
     'babel-preset-es2015',
+    // exponentiation
     'babel-preset-es2016',
-    'babel-preset-stage-0',
+    // JSX, Flow
     'babel-preset-react',
-  ].map(require.resolve),
+  ],
   plugins: [
-    'babel-plugin-transform-react-constant-elements',
-  ].map(require.resolve).concat([
-    [require.resolve('babel-plugin-transform-runtime'), {
+    // function x(a, b, c,) { }
+    'babel-plugin-syntax-trailing-function-commas',
+    // await fetch()
+    'babel-plugin-syntax-async-functions',
+    // class { handleClick = () => { } }
+    'babel-plugin-transform-class-properties',
+    // { ...todo, completed: true }
+    'babel-plugin-transform-object-rest-spread',
+    // function* () { yield 42; yield 43; }
+    'babel-plugin-transform-regenerator',
+    // Polyfills the runtime needed for async/await and generators
+    ['babel-plugin-transform-runtime', {
       helpers: false,
       polyfill: false,
       regenerator: true,
     }],
-  ]),
+    // Optimization: hoist JSX that never changes out of render()
+    'babel-plugin-transform-react-constant-elements',
+  ],
 };