webpack.config.js

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

var config = {
  entry: "./app/index.js",
  output: {
    path: path.resolve(__dirname, "dist"),
    filename: "index_bundle.js",
    publicPath: "/"
  },
  module: {
    rules: [
      { test: /\.(js)$/, use: "babel-loader" },
      { test: /\.css$/, use: ["style-loader", "css-loader"] }
    ]
  },
  mode: "development",
  devServer: {
    historyApiFallback: true
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: "app/index.html"
    })
  ]
};

if (process.env.NODE_ENV === "production") {
  config.plugins.push(
    new webpack.DefinePlugin({
      "process.env": {
        NODE_ENV: JSON.stringify(process.env.NODE_ENV)
      },
      optimization: {
        minimizer: [new UglifyJsPlugin()]
      }
    })
  );
}

module.exports = config;