Multiple await call error handling in NodeJS

user_5151812 0
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I am processing multiple records using async/await and for parallel using Promise.all see my sample code below

  let results = [100,200]
  let promises = results.map(async record => {
   try { 
     return await processingRecords(record);  
   } catch (err) {
   }
  });
  await Promise.all(promises);

async function processingRecords(item) {
 switch (item['#type']) {
    case 'case1':
        await Request1(item)
        await Request2(item)
    break
    case 'case2':
        await Request3(item)
 }
}

But the problem is if Request1 is getting any error I can't catch error from Request2 call how to handle error from both calls

promise async-await node.js ecmascript-6
1 Answers

You can to do a few things here to keep the calls going. Catching errors around the await statements and returning the combined result of Request1 and Request2 will work:

For example: 

async function processingRecords(item) {
    switch (item['#type']) {
        case 'case1':
            let combinedResult = {};
            try { 
                combinedResult.Request1Result = await Request1(item);
            } catch (err) {
                combinedResult.Request1Error = err;
            }
            try { 
                combinedResult.Request2Result = await Request2(item);
            } catch (err) {
                combinedResult.Request2Error = err;
            }
            // Keep the promise chain intact.;
            return combinedResult;
        case 'case2':
            return await Request3(item);
        }
}


let promises = results.map(async record => {
    try { 
        return await processingRecords(record);  
    } catch (err) {
        // Keep the promise chain intact by throwing err here.
        throw err;
    }
});

let overallResult = await Promise.all(promises);
console.log(overallResult);
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