webpack.config.js

const HtmlWebPackPlugin = require('html-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');
const dotenv = require('dotenv');
const webpack = require('webpack');
var path = require('path');

module.exports = () => {
  // call dotenv and it will return an Object with a parsed key
  const env = dotenv.config().parsed || {};

  // reduce env variables to an object
  const envKeys = Object.keys(env).reduce((prev, next) => {
    prev[`process.env.${next}`] = JSON.stringify(env[next]);
    return prev;
  }, {});

  return {
    entry: './src/index.js',
    output: {
      path: path.resolve(__dirname, 'dist'),
      filename: 'bundle.js',
      publicPath: '/',
    },
    module: {
      rules: [
        {
          test: /\.js$/,
          exclude: /node_modules/,
          use: {
            loader: 'babel-loader',
          },
        },
        {
          test: /\.svg$/,
          exclude: /node_modules/,
          use: {
            loader: 'svg-react-loader',
          },
        },
        {
          test: /\.css$/,
          include: /node_modules/,
          loaders: ['style-loader', 'css-loader'],
        },
        {
          test: /\.scss$/,
          use: [
            {
              loader: MiniCssExtractPlugin.loader,
              options: {
                publicPath: '../',
              },
            },
            'css-loader',
            'sass-loader',
          ],
        },
        {
          test: /\.(gif|png|jpe?g)$/i,
          use: [
            'file-loader',
            {
              loader: 'image-webpack-loader',
              options: {
                bypassOnDebug: true, // webpack@1.x
                disable: true, // webpack@2.x and newer
              },
            },
          ],
        },
      ],
    },
    devServer: {
      historyApiFallback: true,
    },
    node: {
      fs: 'empty',
    },
    plugins: [
      new webpack.DefinePlugin(envKeys),
      new HtmlWebPackPlugin({
        template: './src/index.html',
        filename: './index.html',
      }),
      new CopyWebpackPlugin([
        { from: 'src/static/images', to: 'static/images' },
      ]),
      new MiniCssExtractPlugin({
        // Options similar to the same options in webpackOptions.output
        // both options are optional
        filename: 'main.css',
      }),
      new CleanWebpackPlugin(['dist']),
    ],
  };
};