webpack-production.config.js

const webpack = require('webpack');
const path = require('path');
const buildPath = path.resolve(__dirname, 'build');
const nodeModulesPath = path.resolve(__dirname, 'node_modules');

const config = {
  entry: [path.join(__dirname, '/src/index.js')],
  // Render source-map file for final build
  devtool: 'source-map',
  // output config
  output: {
    path: buildPath, // Path of output file
    filename: 'bundle.js', // Name of output file
  },
  plugins: [
    // for React optimized
    new webpack.DefinePlugin({
      'process.env': {
        NODE_ENV: JSON.stringify('production'),
      },
    }),
    // Minify the bundle
    new webpack.optimize.UglifyJsPlugin({
      compress: {
        // supresses warnings, usually from module minification
        warnings: false,
      },
    }),
    // Allows error warnings but does not stop compiling.
    new webpack.NoErrorsPlugin(),

  ],
  module: {
    loaders: [
      {
        test: /\.js$/, // All .js files
        loaders: ['babel-loader'], // react-hot is like browser sync and babel loads jsx and es6-7
        exclude: [nodeModulesPath],
      },
      { 
          test: /\.css$/, 
          loader: "style-loader!css-loader" 
      },
    ],
  },
}

module.exports = config