Stop Promise Chain execution in a recommended way

Question

I have a code similar to this one :

promise_function().then(()=>{
  //do something
  return another_promise_fucntion();
}).then(() => {
  //do something
  return another_promise_function1();
}).then((result) => {
  //check if result is valid
  if(!result)
     //break chain (how to stop calling the next .then functions ?)
  else
     return another_promise_function2();
}).then(()=>{
   //do something
   return another_promise_function3();
}).catch((err)=>{
   //handle error
});

I want to stop calling the next .then() functions, if the returned result is not valid.

I used "throw new Error()", and it worked just fine, but I am not sure if it is the recommended way.

@torazaburo Wouldn't `reject` be an ideal way of doing this? Just asking. — Rajaprabhu Aravindasamy, Apr 23 '17 at 12:31
@RajaprabhuAravindasamy `throw` is the idiomatic way. Yes, `return Promise.reject()` is equivalent, but why bother to do that? — , Apr 23 '17 at 12:41
I think `throw` is the better way because it will to `rejected` state immediately, and can uniform the error structure. return `reject()` is the same way, but you do not give the reject reason, and you need to think about how an object should write in. — 某某某, Jul 26 '22 at 09:43

score 1 · Answer 1 · answered Apr 23 '17 at 12:30

1

It's correct way which recommenced by Mozilla You can see more detail here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/then#Chaining

answered Apr 23 '17 at 12:30

taile

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2

No it's not correct. And I don't see where MDN recommends this pattern? – Bergi Apr 23 '17 at 16:39

Stop Promise Chain execution in a recommended way

1 Answers1