webpack.config.js

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

module.exports = {
  mode: process.env.NODE_ENV,
  entry: './public/index.js',
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'bundle.js'
  },
  devServer: {
    publicPath: 'localhost://8080/build',
    proxy: {
      '/survey/*': 'http://localhost:3000',
      '/user/*': 'http://localhost:3000',
      '/game': 'http://localhost:3000',
      '/socket.io': {
        target: 'http://localhost:3000',
        ws: true
      }
    }
  },
  module: {
    rules: [
      {
        test: /\.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
          process.env.NODE_ENV === 'production' ? MiniCssExtractPlugin.loader : "style-loader",
          // Translates CSS into CommonJS
          "css-loader",
          // Compiles Sass to CSS
          "sass-loader",
        ],
      },
    ]
  }
}