Getting empty array because of the asynchronous nature of Nodejs

Question

Just started working with Nodejs and facing this issue while pushing the array as a response in the below code. I know this is happening because of the asynchronous nature of Nodejs, tried to apply async as well but did not get the desired result. Could someone let me know the fix of this code:

array = [];
  var company = companySchema.Company;
  company.findOne({_id: companySchema.objectId(req.tempStore.companyId)}, function (err, comp) {
    if (err) {
      console.log(err);
     }
     else {
       var i;
       var length = comp.events.length;
       var dataset = datasetSchema.dataset;
       for (i = 0; i < length; i++) {
         dataset.find({companyId:comp.events[i]}, function (err,data) {
           if (err) {
             console.log(err);
           }
           else {
             array.push(data);
           }

             console.log("array-----"+array);  // prints array here
         });
       }
     }
            console.log("array-----"+array);    // array is empty hence causing empty response
             res.response.data = array;
              next();
  });

Kairat · Accepted Answer · 2016-06-16 21:56:07Z

2

You can use mongoDB $in clause for this task:

var company = companySchema.Company;
company.findOne({_id: companySchema.objectId(req.tempStore.companyId)}, function (err, comp) {
    if (err) {
        console.log(err);
    } else {
        var dataset = datasetSchema.dataset;
        dataset.find({companyId : {$in : comp.events}}, function (err, docs) {
            if (err) {
                console.log(err);
            } else {
                console.log("array: " + docs);  // prints array here
                res.response.data = docs;
                next();
            }
        });
    }

});

answered Jun 16, 2016 at 21:56

Kairat

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1 Comment

ani0710 Over a year ago

Ohhh. didn't think this way. Thanks a lot @Kairat

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