Passing a MongoDB collection to an array in NodeJS

Question

I'm having an issue with getting data out of a MongoDB collection and return it into an array in my code in NodeJS.

The code so far returns a promise, that I don't fully know how to handle.

Any help would be appreciated.

async function loadData() {

    try {
        // Connect to the MongoDB cluster
        console.log('Attempting to connect to DB')
        client.connect(async err => {
            const collection = client.db("db").collection("collection");
            await collection.find({}).toArray().then((data) => {

            //Getting stumped as the data gets returned as a promise and does not get added to an array

            }
            );

        client.close();
        console.log('Closed DB connection');

        });
    } catch (e) {
    console.error(e);
    }

chrispytoes · Accepted Answer · 2019-11-21 15:28:45Z

1

You are using promises wrong as well as async await. The purpose of async/await is to avoid using the .then function. Pick one, use either or.

using callback method:

collection.find({}).toArray().then((data) => {
  console.log(data);
}, err => {
  // this gets called if there is an error only
  console.log(err);
});

or with async/await:

try {
  const data = await collection.find({}).toArray();
}
catch(err) {
  console.log(err);
}

note that if you choose to use async/await, the containing function must be marked async, which you're already doing. This is not required if you use the above callback method.

edited Nov 21, 2019 at 15:28

answered Nov 21, 2019 at 15:20

chrispytoes

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Comments

Rebai Ahmed · Accepted Answer · 2019-11-22 08:33:46Z

0

Don't execute the Promise inside the loadData function 


 function loadData() {

    try {
        // Connect to the MongoDB cluster
        console.log('Attempting to connect to DB')
        client.connect(async err => {
            const collection = client.db("db").collection("collection");
            return collection.find({})
            );

        client.close();
        console.log('Closed DB connection');

        });
    } catch (e) {
    console.error(e);
    }

And mak a call to get your Data

try {
  const your_Array = await loadData().toArray();
}
catch(err) {
  console.log(err);
}

And for the MongoDB connection, I think you're doing it wrong , Follow this gist

answered Nov 22, 2019 at 8:33

Rebai Ahmed

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2 Comments

Allan P Over a year ago

Thank you! :) However, I have to note that I'm not using mongoose. Instead, I'm using the official MongoDB connector

Rebai Ahmed Over a year ago

Using an ORM will provide for you more functionality than the official connector !

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