Is there a way to execute some code when a promise is fulfilled, independently from the outcome?

Question

I need to execute the go() method when the promise is fulfilled, even if there is an error. (I am talking to backend API, and I need to do some UI work when I have the server response, even if is a 404).

Now I do this way:

Try.method().then(()=>{
  go();
}).catch({
  go();
})

There is a better way to avoid repeating the method invocation?

Are you asking about a particular promise implementation or the ES6 standard ones? — Bergi, Sep 10 '15 at 13:52

Chrillewoodz · Answer 1 · 2015-09-10T13:24:09.740

2

There is a finally() callback which will be called no matter what the outcome is:

Try.method().then(()=>{
  go();
}).catch({
  go();
}).finally({
  go();
});

Since you are using babeljs which doesn't appear to support the finally() callback you can probably get away with this:

Try.method().catch(()=>{
  go();
}).then({
  go();
})

Where you first catch an error if there is one, if not it will execute the .then() as usual.

edited Sep 10 '15 at 13:24

answered Sep 10 '15 at 12:56

Chrillewoodz

27,055
21
92
175

It doesn't seem to be called in my code – ciaoben Sep 10 '15 at 13:05
@ciaoben This is the way to do something regardless of the outcome. Could you provide a plunkr that illustrates the problem? – Chrillewoodz Sep 10 '15 at 13:09
I am using babeljs, and it says me that is not a method – ciaoben Sep 10 '15 at 13:11
@ciaoben That would explain it, should probably put that as a tag. – Chrillewoodz Sep 10 '15 at 13:12
I was thinking that since every promise callback is chainable, I have added a new `.then()` and it seems to do the job – ciaoben Sep 10 '15 at 13:20
@ciaoben Check my updated answer for another solution. – Chrillewoodz Sep 10 '15 at 13:24

guest271314 · Answer 2 · 2015-09-10T13:13:27.053

There is a better way to avoid repeating the method invocation?

Not certain if interpret above portion of Question correctly ? Try defining a separate .then(go, go) chained to end of api calls

var go = function(data) {
  console.log("go", data)
};

var p = function(args, val) {
  return Promise[args](val)
};

p("resolve", 1).then(go, go);

p("reject", 0).then(go, go);

If can use jQuery, could try utilizing deferred.always()

var go = function(data) {
  console.log("go", data)
};

var p = function(args, val) {
  return $.Deferred()[args](val)
};

p("resolve", 1).always(go);

p("reject", 0).always(go);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">
</script>

Is there a way to execute some code when a promise is fulfilled, independently from the outcome?

2 Answers2