Update webpack.base.conf.js

build/webpack.base.conf.js

@@ -58,6 +58,9 @@ module.exports = {
       {
         test: /\.js$/,
         loader: 'babel-loader?cacheDirectory',
+        options: {
+             presets: ['es2015']
+        },
         include: [resolve('src'), resolve('test')]
       },
       {