webpack.prod.js

const ExtractTextPlugin = require('extract-text-webpack-plugin');
const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
const webpack = require('webpack');
const merge = require('webpack-merge');
const common = require('./webpack.common');

module.exports = merge.smart(common, {
  entry: [
    './app/index.js',
    './scss/main.scss'
  ],
  module: {
    rules: [
      // Pipe other styles through css modules and append to style.css
      {
        test: /\.css$/,
        use: ExtractTextPlugin.extract({
          use: {
            loader: 'css-loader',
          },
        }),
      },
      // Add SASS support  - compile all other .scss files and pipe it to style.css
      {
        test: /\.scss$/,
        use: ExtractTextPlugin.extract({
          use: [
            { loader: 'css-loader' },
            { loader: 'sass-loader' },
          ],
        }),
      },
    ],
  },
  plugins: [
    new UglifyJSPlugin({
      sourceMap: true
    }),
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'production'),
    }),
    new ExtractTextPlugin('style.css')
  ]
});