webpack.config.js

const path = require('path');
const webpack = require('webpack');
const HtmlWebPackPlugin = require('html-webpack-plugin');
const UglifyJsPlugin = require("uglifyjs-webpack-plugin");

module.exports = {
  entry: ['babel-polyfill', './src/index.js'],
  devServer: {
    proxy: {
      '/api': 'http://localhost:3001'
    }
  },
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'bundle.js'
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader"
        }
      },
      {
        test:/\.css$/,
        use:['style-loader','css-loader']
      },
      {
        test: /\.(png|jpg|gif|svg|eot|ttf|woff|woff2)$/,
        loader: 'url-loader',
        options: {
          limit: 10000
        }
      }
    ]
  },

  plugins: [
    new HtmlWebPackPlugin({
      template: 'index.html'
    }),
  ]
};

if (process.env &&
  process.env.NODE_ENV &&
  process.env.NODE_ENV === 'production') {
  const prodOptimization = {
    runtimeChunk: false,
    splitChunks: {
      cacheGroups: {
        commons: {
          test: /[\\/]node_modules[\\/]/,
          name: 'vendors',
          chunks: 'all',
        },
      },
    },
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: true
      })
    ]
  };

  config.optimization = prodOptimization;
}