monkeytype/frontend/webpack/config.prod.js

const { merge } = require("webpack-merge");
const CssMinimizerPlugin = require("css-minimizer-webpack-plugin");
const HtmlMinimizerPlugin = require("html-minimizer-webpack-plugin");
const JsonMinimizerPlugin = require("json-minimizer-webpack-plugin");

const BASE_CONFIGURATION = require("./config.base");

function pad(numbers, maxLength, fillString) {
  return numbers.map((number) =>
    number.toString().padStart(maxLength, fillString)
  );
}

const PRODUCTION_CONFIGURATION = {
  mode: "production",
  module: {
    rules: [
      {
        test: /version\.ts$/,
        loader: "string-replace-loader",
        options: {
          search: /^export const CLIENT_VERSION =.*/,
          replace(_match, _p1, _offset, _string) {
            const date = new Date();

            const versionPrefix = pad(
              [date.getFullYear(), date.getMonth() + 1, date.getDate()],
              2,
              "0"
            ).join(".");
            const versionSuffix = pad(
              [date.getHours(), date.getMinutes()],
              2,
              "0"
            ).join(".");
            const version = [versionPrefix, versionSuffix].join("_");

            return `export const CLIENT_VERSION = "${version}";`;
          },
          flags: "g",
        },
      },
      {
        test: /\.m?js$/,
        exclude: /(node_modules)/,
        use: {
          loader: "babel-loader",
          options: {
            presets: ["@babel/preset-env"],
            plugins: [
              "@babel/plugin-transform-runtime",
              "@babel/plugin-transform-modules-commonjs",
            ],
          },
        },
      },
    ],
  },
  optimization: {
    minimize: true,
    minimizer: [
      `...`,
      new HtmlMinimizerPlugin(),
      new JsonMinimizerPlugin(),
      new CssMinimizerPlugin(),
    ],
  },
};

module.exports = merge(BASE_CONFIGURATION, PRODUCTION_CONFIGURATION);