webpack.prod.js

const merge = require('webpack-merge')
const UglifyJSPlugin = require('uglifyjs-webpack-plugin')
const common = require('./webpack.common.js')
const webpack = require('webpack') // to access built-in plugins
const HtmlWebpackPlugin = require('html-webpack-plugin')
const postcssPresetEnv = require('postcss-preset-env')
const CleanWebpackPlugin = require('clean-webpack-plugin')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const path = require('path')

module.exports = merge(common, {

  target: 'web',
  devtool: 'source-map',
  module: {
    rules: [
      {
        test: /\.scss$/,
        use:

                ExtractTextPlugin.extract({
                  fallback: 'style-loader',
                  use: [
                    { loader: 'css-loader', options: { sourceMap: true, importLoaders: 1 } },
                    { loader: 'postcss-loader',
                      options: {
                        ident: 'postcss',
                        plugins: () => [
                          postcssPresetEnv(/* options */)
                        ]
                      } },
                    { loader: 'sass-loader', options: { sourceMap: true}}

                  ]
                })
      }
    ]
  },
  plugins: [
    new CleanWebpackPlugin(['dist']),
    new UglifyJSPlugin({sourceMap: true}),
    new ExtractTextPlugin('style.css'),
    new HtmlWebpackPlugin({
      title: 'webpack_output',
      template: './src/index.html',
      filename: '200.html'
    })
  ],
  output: {
    filename: 'webpack.bundle.js',
    publicPath: '/',
    path: path.resolve(__dirname, 'dist')
  }

})