webpack.config.js

const path = require('path');
const CleanWebpackPlugin = require('clean-webpack-plugin');
const ManifestPlugin = require('webpack-manifest-plugin');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");

const devMode = process.env.NODE_ENV !== 'production';


module.exports = {

  entry: {
    app: './src/index.js'
  },

  plugins: [
    new CleanWebpackPlugin(['dist']),
    new ManifestPlugin({
      basePath: 'dist/',
      publicPath: 'dist/',
      writeToFileEmit: true
    }),
    new MiniCssExtractPlugin({
      // Options similar to the same options in webpackOptions.output
      // both options are optional
      filename: devMode ? 'css/[name].css' : 'css/[name].[hash].css',
      chunkFilename: devMode ? '[id].css' : '[id].[hash].css',
    })
  ],

  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        loader: "babel-loader"
      },
      {
        test: /\.scss$/,
        use:  [  'style-loader', MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', 'sass-loader']
      }
    ]
  },


  output: {
    filename: '[name].[chunkhash].js',
    path: path.resolve(__dirname, 'dist')
  }
};