webpack.config.js

const path = require("path");
const webpack = require("webpack");
const TerserPlugin = require("terser-webpack-plugin");

module.exports = {
  mode: "production",
  // mode: 'development',
  entry: {
    main: path.join(__dirname, "src", "main.jsx"),
  },
  output: {
    path: path.join(__dirname, "dist"),
    filename: "[name].js",
  },
  resolve: {
    extensions: [".js", ".jsx"],
  },
  module: {
    rules: [
      {
        test: /\.jsx?$/,
        exclude: /node_modules/,
        use: [
          {
            loader: "babel-loader",
            options: {
              presets: ["@babel/preset-env", "@babel/preset-react"],
              plugins: [
                "@babel/plugin-proposal-class-properties",
                "effector/babel-plugin",
              ],
            },
          },
        ],
      },
    ],
  },
  optimization: {
    minimizer: [
      new TerserPlugin({
        terserOptions: {
          parse: {
            // we want terser to parse ecma 8 code. However, we don't want it
            // to apply any minfication steps that turns valid ecma 5 code
            // into invalid ecma 5 code. This is why the 'compress' and 'output'
            // sections only apply transformations that are ecma 5 safe
            // https://github.com/facebook/create-react-app/pull/4234
            ecma: 8,
          },
          compress: {
            ecma: 5,
            warnings: false,
            // Disabled because of an issue with Uglify breaking seemingly valid code:
            // https://github.com/facebook/create-react-app/issues/2376
            // Pending further investigation:
            // https://github.com/mishoo/UglifyJS2/issues/2011
            comparisons: false,
          },
          mangle: {
            safari10: true,
          },
          output: {
            ecma: 5,
            comments: false,
            // Turned on because emoji and regex is not minified properly using default
            // https://github.com/facebook/create-react-app/issues/2488
            ascii_only: true,
          },
        },
        // Use multi-process parallel running to improve the build speed
        // Default number of concurrent runs: os.cpus().length - 1
        parallel: true,
        // Enable file caching
        cache: true,
      }),
    ],
  },
  plugins: [
    new webpack.DefinePlugin({
      "process.env": { NODE_ENV: JSON.stringify("production") },
    }),
  ],
};