Bluebird Promise Cancellation

bluebird-promise-cancellation.js

// Compliant Promise/A+ implementation: https://www.promisejs.org/implementing/
// Alternative implementation: https://dexie.org/docs/Promise/Promise
// Checkout the Node.js Event Loop: https://www.youtube.com/watch?v=PNa9OMajw9w
// Bluebird breaking change: http://bluebirdjs.com/docs/new-in-bluebird-3.html#cancellation-overhaul

const Promise = require('bluebird');

Promise.config({
  cancellation: true,
});

function getPromise() {
  return new Promise((resolve, reject, onCancel) => {
    const handle = setTimeout(() => {
      console.log('I am resolving now...');
      resolve();
    }, 5000);
    onCancel(() => {
      console.log('I am getting canceled.');
      clearTimeout(handle);
    });
  });
}

(async () => {
  const promiseReference = getPromise();
  promiseReference.cancel();
  console.log('Program exits.');
})();