CODEWITHSUNDEEP
javascriptnode.jspromiseaxios
hussain
hussain

Reputation: 7103

How to check error using promises?

I have request coming from client based on params passed i have to make two api calls so in order to achieve that i used promise.all. I am trying to figure out if we have error in 2nd promise how would you catch error on first promise ?

Also if there is any better approach to handle promises in below case please advise i am fairly new to promise.

controller.ts

export function getQuestions(req: Request, res: Response) {


    const p1 = axios.post('http://localhost:9002/getQuestions', req.body).then(
        function(res1) {
            return res1.data.Details;
        });

    const p2 = axios.post('http://localhost:9002/getNoQuestions', req.body).then(
        function(res2) {
            return res2.data;
        });

    Promise.all([p1, p2])
        .then(function(fullResults) {

            const modifiedResults = fullResults;
            res.json(modifiedResults);

        })
        .catch(function(e) {
            console.log(e)
        });
}

Upvotes: 0

Views: 45

Answers (1)

Brandon
Brandon

Reputation: 39192

Add catch clauses to the individual promises instead of relying upon Promise.all error handling

const a = axios.post(...).then(r => r.data.details).catch(e => {
    console.log("error from a: ", e);
});
const b = axios.post(...).then(r -> r.data.details).catch(e => {
    console.log("error from b: ", e);
});

Promise.all([a, b]).then(([aResult, bResult]) => {
   if (aResult && bResult) {
      // do something with results
   }
});

Upvotes: 1

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