mongoose.find() returns empty array with queried result

Question

I need to find my data that matches the particular type. Say, I have an array of objects in my DB, with each object having it's leadType : all or leadType: blacklist. Each object has a different kind of leadType value associated with it.

I want to get the complete data that matches the particular leadType, like leadType: 'radar'.

I tried using the following query but along with the documents it matches, it also returns the empty documents that do not matches the specified projection.

This is what I tried:

exports.leads_by_type = (req, res) => {
  const { lead_type } = req.body;
  Lead.find({}, { leads: { $elemMatch: { leadType: lead_type }}} )
    .then(data => {
      if (!data || data.length === 0) {
        return res.status(404).json({ message: "No data found" });
      }
      res.status(200).json({ message: "Data found", data });
    })
    .catch(err => res.status(500).json({ err }));
};

and it returns me the output as follows:

{
  "message": "Data found",
  "data": [
      {
          "_id": "5e83427079f7611bdc1e48a0",
          "leads": [
              {
                  "education": {
                      "school": "happy kids corner",
                      "graduation": "some school"
                  },
                  "currentPosition": {
                      "title": "Salesforce developer",
                      "endDate": "currently working",
                      "employmentType": "full-time",
                      "industry": "information technology"
                  },
                  "location": {
                      "state": "delhi",
                      "country": "india"
                  },
                  "leadType": "radar",
                  "name": "Ben",
                  "mobile": 1524524678,
                  "_id": "5e83427079f7611bdc1e489e"
              }
          ]
      },
      {
          "_id": "5e84cb4fb59fdd1644e7c226",
          "leads": [
              {
                  "education": {
                      "school": "happy kids corner",
                      "graduation": "some school"
                  },
                  "currentPosition": {
                      "title": "Salesforce developer",
                      "endDate": "currently working",
                      "employmentType": "full-time",
                      "industry": "information technology"
                  },
                  "location": {
                      "state": "delhi",
                      "country": "india"
                  },
                  "leadType": "radar",
                  "name": "joey",
                  "mobile": 1524524678,
                  "_id": "5e84cb4fb59fdd1644e7c224"
              }
          ]
      },
      {
          "_id": "5e84cb70b59fdd1644e7c229",
          "leads": []
      },
      {
          "_id": "5e84cb88b59fdd1644e7c22c",
          "leads": []
      },
      {
          "_id": "5e84cbb7b59fdd1644e7c232",
          "leads": []
      },
      {
          "_id": "5e84cbd9b59fdd1644e7c235",
          "leads": [
              {
                  "education": {
                      "school": "happy kids corner",
                      "graduation": "some school"
                  },
                  "currentPosition": {
                      "title": "Salesforce developer",
                      "endDate": "currently working",
                      "employmentType": "full-time",
                      "industry": "information technology"
                  },
                  "location": {
                      "state": "delhi",
                      "country": "india"
                  },
                  "leadType": "radar",
                  "name": "rhea",
                  "mobile": 1524524678,
                  "_id": "5e84cbd9b59fdd1644e7c234"
              }
          ]
      }
  ]
}

Please help me out to fix remove these empty objects from the data output

Edit: Adding my DB screenshot:

Tarek Essam · Accepted Answer · 2020-04-02 05:27:09Z

1

If you want to match only the documents with leadType equals to radar you should specify this in the find condition.

 exports.leads_by_type = (req, res) => {
  const { lead_type } = req.body;
  Lead.find({ 'leads.leadType': lead_type })
    .then(data => {
      if (!data || data.length === 0) {
        return res.status(404).json({ message: "No data found" });
      }
      res.status(200).json({ message: "Data found", data });
    })
    .catch(err => res.status(500).json({ err }));
};

edited Apr 2, 2020 at 5:27

answered Apr 2, 2020 at 4:57

Tarek Essam

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4 Comments

program_bumble_bee Over a year ago

I tried this too, but then it returns me the complete data with every leadType available

Tarek Essam Over a year ago

The query I wrote will return all documents that have any element in the array of leads with leadType equal to radar. If you want to return the array with the elements containing leadType radar only, then please tell me

program_bumble_bee Over a year ago

Yes, I want to return documents containing the leadType equal to 'radar' only. The query I originally wrote, gives me the documents with type radar. and also, where the type is not equal to radar, it returns an empty array. I want to eliminate that.

program_bumble_bee Over a year ago

I have edited my question with my existing db. Can you please check with that?

Niraj Patel · Accepted Answer · 2020-04-02 05:32:03Z

1

find({ leads: { $elemMatch: { leadType: lead_type }}} )

You can try the above query.

{} you had used empty object along with your condition in find which is the root cause behind the fetched empty data.

edited Apr 2, 2020 at 5:32

answered Apr 2, 2020 at 5:11

Niraj Patel

8108 silver badges16 bronze badges

6 Comments

program_bumble_bee Over a year ago

Still the same result. It returns me the complete data with every leadType available

Niraj Patel Over a year ago

@bubble-cord, mongoplayground.net/p/5Pw--9W9akB - This one is with the query I mentioned above mongoplayground.net/p/YiMPGQh4Vsa - This one is the query you had used You can find the difference in result.

program_bumble_bee Over a year ago

Can you please create a chat for this? I am still unable to rectify my issue?

program_bumble_bee Over a year ago

I have edited my question with my existing db. Can you please check with that?

Niraj Patel Over a year ago

Can you just copy above mentioned find portion and replace with the find portion in your query and check the output?

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