Could not iterate asynchrous function inside loop using MongoDB and Node.js

Question

I am unable to call mongoDB callback function inside the loop. I am providing my array and code below.

[
    {
        "location": "NEW DELHI",
        "nos_of_fos": 15,
        "login_id": [
            "9619300317",
            "9619300343",
            "9619300338",
            "9619300351",
            "9619300322",
            "9619300316",
            "9619300323",
            "9619300328",
            "9619300341",
            "9619300309",
            "9619300310",
            "9619300329",
            "9619300353",
            "9619300356",
            "[email protected]"
        ],

    },
    {
        "location": "North West Delhi",
        "nos_of_fos": 6,
        "login_id": [
            "9619300355"
        ],

    }
]

The above is my input array.

finalOut.forEach(function(listItem, index){
                    var remarkCount=0;
                    console.log('items',listItem['login_id']);
                    listItem['login_id'].forEach(function(item, index1){
                        Feedback.collection.countDocuments({login_id:item},function(cerr,cdocs){
                            if (!err) {
                                if (docs >0) {
                                    console.log('docsinner',cdocs);
                                    remarkCount+=parseInt(cdocs);
                                }
                            }
                        })
                    })
                    console.log('docsout',remarkCount);
                    finalOut[index]['total_remarks']=remarkCount;
                })

Here before finishing mongoDB checking for first iteration loop getting finished. Here I need to check one by one login_id value and only after finishing the mongoDB task new count will assign.

@AshokMandal: you can check it.there is no total_remarks value there. and also no console message are executing. — satya
– satya, Commented Jan 25, 2019 at 10:02

Ashok Mandal · Accepted Answer · 2019-01-25 09:45:53Z

1

finalOut.forEach(function(listItem, index) {
  var remarkCount = 0;

  var promises = listItem['login_id'].map(function(item, index1) {
    return new Promise((resolve, reject) => {
      Feedback.collection.countDocuments({ login_id: item }, function(
        err,
        docs
      ) {
        if (!err) {
          if (docs > 0) {
            console.log('docsinner', docs);
            remarkCount += parseInt(docs);
          }
          resolve();
        }
        reject();
      });
    });
  });
  Promise.all(promises)
    .then(() => {
      finalOut[index]['total_remarks'] = remarkCount;
    })
    .catch(err => {});
});

answered Jan 25, 2019 at 9:45

Ashok Mandal

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1 Comment

satya Over a year ago

there is no total_remarks value in the final array.

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