Объясните, как можно написать (или напишите) адаптеры асинхронности promisify и callbackify?nodejs-21

function promisify(original) {
  return function(...args) {
    return new Promise((resolve, reject) => {
      original.call(this, ...args, (err, result) => {
        if (err) {
          reject(err);
        } else {
          resolve(result);
        }
      });
    });
  };
}

const fs = require('fs');
const readFilePromise = promisify(fs.readFile);

readFilePromise('file.txt', 'utf8')
  .then(data => console.log(data))
  .catch(err => console.error(err));

function advancedPromisify(original) {
  return function(...args) {
    return new Promise((resolve, reject) => {
      original.call(this, ...args, (err, ...results) => {
        if (err) {
          reject(err);
        } else {
          resolve(results.length > 1 ? results : results[0]);
        }
      });
    });
  };
}

function callbackify(promiseFn) {
  return function(...args) {
    const callback = args.pop();
    if (typeof callback !== 'function') {
      throw new TypeError('Callback must be a function');
    }

    promiseFn.apply(this, args)
      .then(result => callback(null, result))
      .catch(err => callback(err));
  };
}

async function asyncFetchData(url) {
  // Реализация с async/await
}

const callbackFetchData = callbackify(asyncFetchData);

callbackFetchData('https://api.example.com', (err, data) => {
  if (err) return console.error(err);
  console.log(data);
});

function advancedCallbackify(promiseFn) {
  return function(...args) {
    const callback = args.pop();
    if (typeof callback !== 'function') {
      return promiseFn.apply(this, args);
    }

    try {
      const result = promiseFn.apply(this, args);
      if (result && typeof result.then === 'function') {
        result.then(
          val => callback(null, val),
          err => callback(err)
      } else {
        callback(null, result);
      }
    } catch (err) {
      callback(err);
    }
  };
}

const { promisify } = require('util');
const sleep = promisify(setTimeout);

await sleep(1000); // Ждет 1 секунду

const { callbackify } = require('util');
const callbackAsyncFn = callbackify(asyncFn);