promise.js

const pp = function() {
  return new Promise((resolve, reject) => {
    let r = (Math.round(Math.random() * 5, 0));
    if (r > 3) {
      setTimeout(() => resolve(r), r * 1000);
    } else {
      reject(`${r} is not enough`);
    }
  });
};

pp().then((r) => console.log(r))
  .catch(err => console.error(err))
  .finally(() => console.log('always runs'));

(async function() {
  try {
    let r = await pp();
    console.log('await version: ' + r);
  } catch (err) {
    console.error('await error: ', err);
  } finally {
    console.log('await always runs');
  }
})();