title: Webpack doesn't render sass correctly when not exporting file
body: <p>I am trying to configure Webpack 4 to use Sass for a MERN project. When I use <em>mini-css-extract-plugin</em> and export a CSS file and then link it in the index.html file it works. However, when I try to bundle the css with the bundle.js file, it will not render the css and the odd thing is, it does not render just some parts of it. I tried following the official bootstrap webpack installation, but it did not work as intended. </p>
  
  <p>Here are the files:</p>
  
  <p><strong>webpack.config.js:</strong></p>
  
  <pre><code>const path = require('path');
  // const MiniCssExtractPlugin = require('mini-css-extract-plugin');
  module.exports = {
    entry: './client/src/index.js',
    mode: 'development',
    module: {
      rules: [
        {
          test: /\.s?css$/,
          exclude: /node_modules/,
          use: [
            {
              loader: 'style-loader',
            },
            {
              loader: 'css-loader',
              options: {
                localIdentName: '[name]__[local]__[hash:base64:5]',
                modules: true,
                importLoaders: 1,
                sourceMap: true,
              },
            },
            {
              loader: 'sass-loader'
            },
          ],
        },
          {
              test: /\.js$/,
              exclude: /node_modules/,
              loader: "babel-loader",
              options: {
                  presets: ['@babel/preset-env']
              }
          },
          {
            test: /\.jsx$/,
            exclude: /node_modules/,
            loader: "babel-loader",
            options: {
                presets: ['@babel/preset-env']
            }
          }
        ]
    },
    output: {
      path: path.resolve(__dirname, 'client/public'),
      filename: 'bundle.js'
    }
  }
  </code></pre>
  
  <p><strong>./client/src/index.js:</strong></p>
  
  <pre><code>import React from 'react';
  import ReactDOM from 'react-dom';
  import { BrowserRouter } from 'react-router-dom';
  
  import 'bootstrap';
  import '../sass/style.scss'
  import App from './components/App';
  
  ReactDOM.hydrate(
      &lt;BrowserRouter&gt;
        &lt;App /&gt;
      &lt;/BrowserRouter&gt;,
      document.getElementById('root')
  )
  </code></pre>