Rough function to write a Webpack config to a file

writeWebpackConfigToFile.js

const { writeFileSync } = require('fs-extra');
const { EOL } = require('os');

/**
 * Function to write a Webpack config to a file.
 * Helpful when debugging a Webpack config from a tool or library.
 * Several aspects here could be improved, but this is merely a rough take.
 * 
 * @param {string} destPath
 * @param {import('webpack').Configuration} config
 */
function writeWebpackConfigToFile(destPath, config) {
  const stringified = JSON.stringify(
    config,
    (_, value) => {
      // is RegExp
      if (Object.prototype.toString.call(value) === '[object RegExp]') {
        return `/${value.source}/${value.flags}`;
      }

      // Serialize Typescript in a manageable format
      if (
        key.toUpperCase() === 'TYPESCRIPT' &&
        'version' in value &&
        'versionMajorMinor' in value
      ) {
        return `{ [package code: typescript ${value.version}] }`;
      }

      // is function
      if (typeof value === 'function') {
        return value.toString();
      }

      return value;
    },
    '  '
  );

  const fnRegExp = /\"(function(?:.*)})\"/gim;
  const regexpRegExp = /\"(\/[^\*](?:.*)\/)\"/gim;

  const somewhatRehydrated = stringified
    .replace(regexpRegExp, (_, str) => str.replace(/\\\\/gim, '\\'))
    .replace(/\"\{\s+(\[package code: (?:.+)\])\s+\}\"/gim, (_, str) => `{ /* ${str} */ }`)
    .replace(fnRegExp, (_, str) =>
      str
        .replace(/(\\n)/gim, EOL)
        .replace(/(\[native code\])/gim, str => `/* ${str} */`)
        .replace(/(\\")/gim, '"')
        .replace(/(\\\\')/gim, "\\'")
    );

  writeFileSync(destPath, `exports.module = () => {\nreturn ${somewhatRehydrated};\n};`);
}