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,
  module: {
    rules: [
      {
        test: /.jsx?$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-react', '@babel/preset-env']
          }
        }
      },
      {
        test: /.(scss|sass|css)$/,
        use: ["style-loader", "css-loader", "sass-loader"]
      },
    ]
  },
  plugins: [
    new HTMLWebpackPlugin({template: './index.html'})
  ],
  devServer: {
    static: {
      directory: path.resolve(__dirname, 'build'),
      publicPath: '/'
    },
    port: 8080,
    proxy: {
      '/api': 'http://localhost:3000'
    }
  }
}