webpack.config.js

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

module.exports = {
  entry: './client/index.js',
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'bundle.js',
  },
  mode: process.env.NODE_ENV,
  devServer: {
    static: {
      directory: path.join(__dirname, 'build'), // where we're looking
      publicPath: '/build',
    },
    // re-routing api fetch calls to localhost 3000 (which has access to express)
    proxy: {
      '/api': {
        target: 'http://localhost:3000',
        pathRewrite: { '^/api': '' }, // or use '/*' instead of '/api' to take care of all other fetch calls
      }
     }
  },
  plugins: [
    new HtmlWebpackPlugin({
    template: './index.html',
  })
  ],
  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: [
          // Creates `style` nodes from JS strings
          "style-loader",
          // Translates CSS into CommonJS
          "css-loader",
          // Compiles Sass to CSS
          "sass-loader",
        ],
      },
      {
        test: /\.(png|jpe?g|gif)$/i,
        use: [
          {
            loader: 'file-loader',
          },
        ],
      },
    ],
  },
}