webpackConfig.js

  var babelLoader = 'babel?presets[]=es2015&presets[]=react&plugins[]=syntax-object-rest-spread';

  if (opts.hot) {
    config.entry.app = [
      'webpack-dev-server/client?' + opts.publicPath,
      'webpack/hot/only-dev-server',
      config.entry.app,
    ];
    config.module.loaders.push({
      test: /\.jsx?$/,
      include: path.resolve('./src'),
      exclude: [
        /node_modules/,
        path.resolve('./src/common/annotator-full.js')
      ],
      loader: 'react-hot!' + babelLoader,
    });
    config.plugins.push(new webpack.HotModuleReplacementPlugin());
  }
  else {
    config.module.loaders.push({
      test: /\.jsx?$/,
      include: path.resolve('./src'),
      exclude: [
        /node_modules/,
        path.resolve('./src/common/annotator-full.js')
      ],
      loader: babelLoader,
    });
  }