title: Webpack Extract-Text-Plugin Output Multiple CSS Files (Both Minified and Not Minified)
body: <p>I write style in SCSS, and I want to use webpack to build both minified and not minified css files.
  So I set my webpack.config.js:</p>
  
  <pre><code>const path = require('path');
  const webpack = require('webpack');
  const ExtractTextPlugin = require('extract-text-webpack-plugin');
  
  const extractSASS = new ExtractTextPlugin('assets/styles/[name].css');
  const extractMiniSASS = new ExtractTextPlugin('assets/styles/[name].min.css');
  
  module.exports = {
      entry: './Scripts/main.js',
      output: { path: path.resolve(__dirname, 'wwwroot/'), filename: 'scripts/bundle.js' },
      module: {
          rules: [
              {
                  test: /\.scss$/,
                  use: extractSASS.extract({
                      use: ['css-loader', 'sass-loader'],
                  }),
              },
              {
                  test: /\.scss$/,
                  use: extractMiniSASS.extract({
                      use: [{ loader: 'css-loader', options: { minimize: true } }, 'sass-loader'],
                  }),
              },
              {
                  test: /\.js$/,
                  use: [{ loader: 'babel-loader', options: { presets: ['es2015'] } }],
              },
          ],
      },
      plugins: [new webpack.optimize.UglifyJsPlugin(), extractSASS, extractMiniSASS],
  };
  </code></pre>
  
  <p>But after I run <code>npm run build</code>, I get some errors:</p>
  
  <pre><code>ERROR in ./SCSS/main.scss
  Module build failed:
  $primary_color: #99dd00;
  ^
        Invalid CSS after "e": expected 1 selector or at-rule, was "exports = module.ex"
        in D:\Test\WebpackTest\CSSLoaderTest\SCSS\main.scss (line 1, column 1)
   @ ./Scripts/main.js 3:0-28
  Child extract-text-webpack-plugin node_modules/extract-text-webpack-plugin/dist node_modules/css-loader/index.js!node_modules/sass-loader/lib/loader.js!node_modules/extract-text-webpack-plugin/dist/loader.js??ref--1-0!node_modules/css-loader/index.js??ref--1-1!node_modules/sass-loader/lib/loader.js!SCSS/main.scss:
         [0] ./node_modules/css-loader!./node_modules/sass-loader/lib/loader.js!./node_modules/extract-text-webpack-plugin/dist/loader.js?{"id":2,"omit":0,"remove":true}!./node_modules/css-loader?{"minimize":true}!./node_modules/sass-loader/lib/loader.js!./SCSS/main.scss 159 bytes {0} [built]
          + 1 hidden module
  npm ERR! code ELIFECYCLE
  npm ERR! errno 2
  npm ERR! cssloadertest@1.0.0 build: `webpack`
  npm ERR! Exit status 2
  npm ERR!
  npm ERR! Failed at the cssloadertest@1.0.0 build script.
  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
  
  npm ERR! A complete log of this run can be found in:
  npm ERR!     C:\nodejs\node_cache\_logs\2018-01-24T03_09_52_242Z-debug.log
  </code></pre>
  
  <p>If my webpack.config.js is error? How should I solve it?</p>