feat(finally): finally should receive as parameter the state of the promise

As per https://github.com/angular/angular.js/issues/9246 , it would be nice and more developer friendly to be able to receive the state of the promise inside the finally call.

My suggestion is for .fin() to receive 2 parameters:

1. a boolean – if the promise was resolved (TRUE) or rejected (FALSE)
2. a mixed – value sent to .resolve() or .reject()

@kriskowal : what do you think?

I’ll post here the real use-case again. We have a SPA and we are using AngularJS as a framework. I know Q service is a bit different than AngularJS $q, but the logic seems to be very similar.

Our use-case is when all the ajax requests (error or success) may contain a set of messages - those messages should be automatically pushed to the messages component and be shown. The problem is that we have to write:

.then(
  function (data) {
    msgService.notify(data);
  },
  function (data) {
    msgService.notify(data);
  }
);


My suggestion was to have something like:
.then(...)
.finally(function (isResolved, data) {
    msgService.notify(data);
});

We can even adapt our notify and just put “.finally(msgService.notify)”.

[thatshailesh]

@domenic How would you implement something like

Promise.reject(new Error("boo!"))
  .catch(function () { console.log('it should not go to next promise') })
  .then(function () { console.log("I should be called only if there is no error"); });

Below code doesn’t work since .finally() doesn’t take any arguments

.then((something) => {
  return () => { something.log(...) }
})
.catch(next)
.finally(cb => {
  //check if cb === function
  cb.call(this)
})

One way to do that is

Promise.reject(new Error("boo!"))
  .catch(function (err) { next(err); 
     return {notify: false}
 })
.then(res => {
  if (res.notify) { console.log("I should be called only if there is no error"); }}
})

Any other cleaner way to achieve the same?

[benjamingr]

That train has sailed by now - finally is part of JavaScript.

Also, you should just do:

Promise.reject(new Error(“boo!”)) .then(function () { console.log(“I should be called only if there is no error”); }, function () { console.log(‘it should not go to next promise’) });

Or, for this behavior do what synchronous code would (and rethrow the error with a throw).

Also, it is considered bad etiquette to bump issues from 2014