promise-exception-handling.js

// Promise exception handling is actually handled by mulitple level - therfore you need to care about many things
new Promise((res, rej) => {
    setTimeout(_ => {
      // case 1) error outside of promise context
      res('booom 2');
      throw new Error('error 2'); // this won't get ignored like case 1 and have to be catched manually. Also this don't automatically goes to `onRejected` handler unlike case 1.
    }, 3000);
    // case 2)
    // res('booom 1');
    // throw new Error('error 1'); // This gets ignored because it is thrown after resolve function gets called.
})
.then(function onFulfilled(res) {
  throw new Error('error in onFulfilled'); // This error will be catched and handled by to catch();, if fulfilled.
  console.debug('fulfilled', res);
}, function onRejected(res) {
  throw new Error('error in onRejected');
  console.debug('rejected', res);
})
.catch(err => {
  console.debug('Caught error from catch()', err)
});