webpack.config.js

const path = require('path');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
  // mode
  mode: process.env.NODE_ENV,
  // entry
  entry: ['./client/index.js'],
  output: {
    path: path.resolve(__dirname, './build'),
    filename: 'bundle.js',
  },
  // dev server settings
  devServer: {
    publicPath: '/build/',
    proxy: [
      {
        context: ["/api", "/login", "/image"],
        target: 'http://localhost:3000',
      },
    ],
    hot: true,
  },
  // allow importing without expliciity stating .js and .jsx file extensions
  resolve: {
    extensions: ['.js', '.jsx', '.scss'],
  },
  // plugins
  plugins: [
    new MiniCssExtractPlugin({
      filename: 'style.css',
    }),
  ],
  // loaders
  module: {
    rules: [
      // react loader
      {
        test: /\.jsx?$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env', '@babel/preset-react'],
          },
        },
      },
      // sass loader
      {
        test: /\.s?[ac]ss$/,
        use: [
          // Creates `style` nodes from JS strings
          {
            loader: MiniCssExtractPlugin.loader,
            options: {
              hmr: process.env.NODE_ENV === 'development',
            },
          },
          // Translates CSS into CommonJS
          'css-loader',
          // Compiles Sass to CSS
          'sass-loader',
        ],
      },
    ],
  },
};