webpack.config.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");

module.exports = (env, argv) => {
  const isProd = argv.mode === "production";
  const isDev = !isProd;

  console.log("isProd", isProd);
  console.log("isDev", isDev);

  const filename = (ext) =>
    isProd ? `[name].[contenthash].bundle.${ext}` : `[name].bundle.${ext}`;

  return {
    target: "web",
    context: path.resolve(__dirname, "src"),
    entry: {
      main: ["core-js/stable", "regenerator-runtime/runtime", "./app.js"],
    },
    output: {
      path: path.resolve(__dirname, "dist"),
      filename: filename("js"),
      clean: true,
    },
    resolve: {
      extensions: [".js"],
      alias: {
        "@": path.resolve(__dirname, "src"),
      },
    },
    devServer: {
      port: "3000",
      open: true,
    },
    devtool: isDev ? "source-map" : false,
    plugins: [
      new HtmlWebpackPlugin({
        template: "./index.html",
      }),
      new MiniCssExtractPlugin({
        filename: filename("css"),
      }),
    ],
    module: {
      rules: [
        {
          test: /\.css$/i,
          use: [MiniCssExtractPlugin.loader, "css-loader"],
        },
        {
          test: /\.m?js$/,
          exclude: /node_modules/,
          use: {
            loader: "babel-loader",
            options: {
              presets: ["@babel/preset-env"],
            },
          },
        },
      ],
    },
  };
};