Simple promises creation from callbacks API

promesify.js

/* Callbacks function */

const asyncFn = (i, success, error) => {
  if (i === 0) return error('Failed!');
  setTimeout(() => {
    return success('Worked!!');
  }, 1000);
};

/* Function call like in old times */

asyncFn(
  1,
  res => {
    console.log('Timed Out Freund!', res);
  },
  error => {
    console.log('Ups', error);
  }
);

/* Promesify method */
const promesify = fn => {
  return (...params) => ({
    then: cbThen => ({
      catch: cbCatch => {
        fn(...params, cbThen, cbCatch);
      }
    })
  });
};

/* Promesified function */

const asyncFnPromised = promesify(asyncFn);

/* Promesified function call */

asyncFnPromised(0)
  .then(res => {
    console.log('Timed Out Alter!', res);
  })
  .catch(error => {
    console.log('Timed Out Exploded!', error);
  });

It isn't actually promisified because you can't chain the promises or use async/await. A similar function would do the trick:

const promisify =
  (fn) =>
  (...params) =>
    new Promise((resolve, reject) => fn(...params, resolve, reject));