webpack.common.js

const path = require('path');

const SRC_DIR = path.join(__dirname, 'client/src');
const DIST_DIR = path.join(__dirname, 'client/public');

module.exports = {
  mode: 'development',
  entry: SRC_DIR,
  output: {
    path: DIST_DIR,
    filename: 'bundle.js',
    publicPath: '/',
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: [
              '@babel/preset-env',
              '@babel/react',
            ],
          },
        },
      },
      {
        test: /\.css$/,
        use: [
          {
            loader: 'style-loader',
          },
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1,
              modules: true,
            },
          },
        ],
      },
    ],
  },
};