webpack.config.js

const path = require('path');
const HTMLWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  mode: process.env.NODE_ENV,
  entry: path.resolve(__dirname, '/client/index.js'),

  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'bundle.js',
  },

  plugins: [
    new HTMLWebpackPlugin({
      // filename: 'index.html',
      title: 'Development',
      template: './client/index.html',
    }),
  ],

  devServer: {
    host: 'localhost',
    port: '8080',
    proxy: {
      '**': 'http://localhost:3000',
    },
    historyApiFallback: true,
    static: {
      directory: path.resolve(__dirname, 'build'),
      publicPath: 'build',
    },
  },

  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env', '@babel/preset-react'],
          },
        },
      },
      {
        test: /\.s[ac]ss$/i,
        use: ['style-loader', 'css-loader', 'sass-loader'],
      },
    ],
  },
  resolve: {
    extensions: ['.js', '.jsx'],
  },
};