Why returned data from mongodb find() is not giving any data in api route?

Question

What is wrong with this result? my res.send(dbResult) is not giving me any data. It is empty.

/* GET users listing. */
router.get('/', function(req, res, next) {

  async function getData(){
    try{
     var dbResult = await mongodb.findData("contacts","iyaiContacts");
     console.log('before dbResult');
     res.send (dbResult);
    }catch(error){
      console.log("error getting contacts...", error.message);
    }
  }
  getData();
});

Additional code for clarity. I have a db.js file that is used to handle the MongoDB connections and queries. Here is the Find Data function. Sorry I didn't realize I was being confusing until people asked questions.

const findData = (myColl, myDb) => {
  try {
    MongoClient.connect(
      url,
      function(err, client) {
        client
          .db(myDb)
          .collection(myColl)
          .find()
          .sort({ nmFull: 1 })
          .toArray(function(err, result) {
            console.log("find() result...", result);
            return result;
          });
      }
    );
  } catch (e) {
    console.log(`findData() error message is...${e.message}`);
    client.close(); // trying to close open db connection if it exist
    throw e;
  }
};

The word “async” before a function means one simple thing: a function always returns a promise. — chridam, Jan 19 '19 at 08:45
Which package your using to connect mongoDB ?. Usually it will be like .find(), what is .findData() mean ? — Şivā SankĂr, Jan 19 '19 at 09:09

Şivā SankĂr · Accepted Answer · 2019-01-20T04:42:47.773

You are writing a backend service for your app that need to fetch data from your MongoDB. The problem is that your handling functions in synchronous manor — instead you need to handle as asynchronous.

// Quick fix for your code

const findData = (myColl, myDb) => {
    return new Promise(function (resolve, reject) {
        MongoClient.connect(url)
            .then((client) => {
                return client.db(myDb)
            }).then((db) => {
                return db.collection(myColl).find().sort({ nmFull: 1 })
                    .toArray((err, result) => { resolve(result); });
            }).catch((err) => {
                reject(err);
            });
    });
};

Here are some best practice to connect MongoDB on Node.js,

Thanks for your help. That worked in my code. I didn't realize the db call was causing the issue. I thought it was in the API. — Trewaters, Jan 20 '19 at 14:32

Why returned data from mongodb find() is not giving any data in api route?

1 Answers1