webpack.config.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const DotEnvPlugin = require('dotenv-webpack');

module.exports = {
  entry: ['@babel/polyfill', './src/index.js'],
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'bundle.js',
    publicPath: '/',
  },
  module: {
    rules: [{
      test: /\.(js|jsx)$/,
      exclude: /node_modules/,
      use: {
        loader: 'babel-loader',
      },
    },
    {
      test: /\.(css|scss)$/,
      use: [
        'style-loader', // creates style nodes from JS strings
        'css-loader', // translates CSS into CommonJS
        'sass-loader', // compiles Sass to CSS, using Node Sass by default
      ],
    },
    {
      test: /\.(gif|png|jpe?g|svg)$/i,
      use: [
        'file-loader',
        {
          loader: 'image-webpack-loader',
          options: {
            mozjpeg: {
              progressive: true,
              quality: 65,
            },
            // optipng.enabled: false will disable optipng
            optipng: {
              enabled: false,
            },
            pngquant: {
              quality: '65-90',
              speed: 4,
            },
            gifsicle: {
              interlaced: false,
            },
            // the webp option will enable WEBP
            webp: {
              quality: 75,
            },
          },
        },
      ],
    },
    ],
  },
  devServer: {
    port: process.env.PORT || 8080,
    contentBase: path.join(__dirname, 'src'),
    historyApiFallback: true,
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: './src/index.html',
    }),
    new DotEnvPlugin({ systemvars: true }),
  ],
  resolve: {
    extensions: ['.js', '.jsx', '.scss'],
  },
};