Typescript Handling promise errors

Question

In a controller I have multiple calls to some methods that return a promise.

I'm going to use the await/async statement and I have something like this:

try {
  let foo = await myFirstMethod();
  let bar = await mySecondMethod();
}catch(e => {
  // which method fails between the both?
});

Yes, I know that I could split the call in two separate try/catch statement, but I have to handle also this scenario and in addiction I'd like to understand which is the better way to have a specific type of error response for each methods.

Any helps or suggestions are appreciated and welcome.

Thanks

It depends on what your first and second method throw. You could distinguish on the error message or you could different concrete error Implementation. — k0pernikus, Jun 03 '21 at 15:34
Possible duplicate of [Correct Try…Catch Syntax Using Async/Await](https://stackoverflow.com/q/44663864/1048572) - or is there something typescript-specific you want to know? — Bergi, Jun 03 '21 at 16:31

code_monk · Answer 1 · 2021-06-04T04:06:55.590

0

What you're looking for is Promise.allSettled

let promises = [myFirstMethod() ,mySecondMethod()];

let allResults = Promise.allSettled(promises).then((results) => {
    // results is an array of objects representing the promises' final state
    // result.status is either "fulfilled" or "rejected"

   results.forEach(result => {
       console.log(result.status);
   });

});

edited Jun 04 '21 at 04:06

answered Jun 03 '21 at 15:49

code_monk

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You forgot to call the methods in your `promises` array creation – Bergi Jun 03 '21 at 16:17
1

I don't think this is what the OP wants. They were running two async methods sequentially, your code changes this to concurrent execution without good reason. – Bergi Jun 03 '21 at 16:18
No, promises are not "invoked". As you say, `Promise.allSettled` accept an array of promises, but you have to call `myFirstMethod()` and `mySecondMethod()` to *create* these promises. – Bergi Jun 03 '21 at 19:09
1

updated code per @Bergi's note, however, complaints about sequential execution still valid. This is perhaps not the best way to address OP's need – code_monk Jun 04 '21 at 04:10

Typescript Handling promise errors

1 Answers1