CODEWITHSUNDEEP
javascriptnode.jsasync-await
Xp.L
Xp.L

Reputation: 885

Not all of the elements after an async/await in an Array.map() call get resolved

I have posted a question in this post earlier. It finally shows some output after changing synchronous functions into asynchronous; however, it turns out that in the output array, some of the elements are null. I am not sure why?

the main code looks like this:

router.post('/form1',  async (req, res, next)=>{

try{
    const emdate = new Date(req.body.emdate);
    const address = req.body.address;
    const stationDataCursor = stationData.filteredData(instantData, emdate);

    stationDataCursor.toArray().then(async (docArr)=>{


            return await Promise.all(docArr.map(async function(val, ind){

                try {
                    const feature = await calcDSV.calcDSV(val);                        
                    return feature

                } catch (error) {

                    console.log(ind);
                    console.log("Error happened in data array", error);

                }

            }));


    }).then((doc)=>{
        res.json(doc)
    })

} catch(error){
    res.status(400).send(error)
}
})

I tried add Promise.resolve(featureJSON) in the return of calcDSV(val)

async function calcDSV(featuresJSON){

    // featuresJSON  
    const SVscore = [];
    const tuEval = featuresJSON.features.properties.TU90; // array
    const obArr = featuresJSON.features.properties.OB; // array
    const periodObj = await getPeriods(tuEval);// get period position
    const paramObj = await getParams(periodObj, obArr); // get parameters
    const periodDate =  await getPeriodDate(featuresJSON, periodObj);
    const removeTime =  periodDate.beginDate.map(x=>x.split('T')[0]);


    let hourly = paramObj.hourCounts;
    let avgTemps = paramObj.avgTemps;


    for(let i = 0;i<hourly.length; i++){

        let score = await assignScore(avgTemps[i], hourly[i]);
        SVscore.push(score);

    }

    // output sv score for date


    const aggreScore = await accumScore(removeTime, SVscore);


    aggreScore.DSVdate = aggreScore.Date.map(x=>new Date(x));


    featuresJSON.features.properties.periodSV = SVscore;
    featuresJSON.features.properties.Periods = periodDate;
    featuresJSON.features.properties.DSVscore = aggreScore;

    return  Promise.resolve(featuresJSON);
}


module.exports.calcDSV = calcDSV;

The error message:

2
Error happened in data array ReferenceError: error is not defined
at getParams (/media/swaggyp1985/HDD4T/OSU_Projects_2017-2018/App_Projects/wallin_model/dev/dev_js/wallin-server/src/utils/periodFunc.js:145:9)
at Object.calcDSV (/media/swaggyp1985/HDD4T/OSU_Projects_2017-2018/App_Projects/wallin_model/dev/dev_js/wallin-server/src/utils/wallinLogic.js:842:32)
at processTicksAndRejections (internal/process/task_queues.js:86:5)
6
Error happened in data array ReferenceError: error is not defined
at getParams (/media/swaggyp1985/HDD4T/OSU_Projects_2017-2018/App_Projects/wallin_model/dev/dev_js/wallin-server/src/utils/periodFunc.js:145:9)
at Object.calcDSV (/media/swaggyp1985/HDD4T/OSU_Projects_2017-2018/App_Projects/wallin_model/dev/dev_js/wallin-server/src/utils/wallinLogic.js:842:32)
at processTicksAndRejections (internal/process/task_queues.js:86:5)
...

I expect every element would be resolved.

Upvotes: 2

Views: 75

Answers (1)

Xp.L
Xp.L

Reputation: 885

Thanks to the comments, I was able to find out the source: the throw error() in other functions I defined. It should be throw Error().

Upvotes: 1

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