Node.js mongodb driver async/await queries

Since all answers are missing some bits (catch blocks, checking that client is not null) I came with my own solution. Tested with Mongo server v4.0.7 and Node JS driver 3.2.2.

Note that the example is a console program, where we close the connection to the server in the finally block. In a web application, the connections are reused. See Node Mongo docs. Also, the errors are logged with libraries such as Winston or Morgan and not console logged.

const MongoClient = require('mongodb').MongoClient;

const url = 'mongodb://localhost:27017';

async function findOne() {

    const client = await MongoClient.connect(url, { useNewUrlParser: true })
        .catch(err => { console.log(err); });

    if (!client) {
        return;
    }

    try {

        const db = client.db("testdb");

        let collection = db.collection('cars');

        let query = { name: 'Volkswagen' }

        let res = await collection.findOne(query);

        console.log(res);

    } catch (err) {

        console.log(err);
    } finally {

        client.close();
    }
}

await findOne();

Edit: 'mongodb' v3.x

according to mongoDB ES6 future you can use this way;

let MongoClient = require('mongodb').MongoClient;
const connectionString = 'mongodb://localhost:27017';

    (async () => {
        let client = await MongoClient.connect(connectionString,
            { useNewUrlParser: true });

        let db = client.db('dbName');
        try {
           const res = await db.collection("collectionName").updateOne({ 
               "someKey": someValue
           }, { $set: someObj }, { upsert: true });

           console.log(`res => ${JSON.stringify(res)}`);
        }
        finally {
            client.close();
        }
    })()
        .catch(err => console.error(err));

Thanks. Working great with ES6:

const middleWare = require('middleWare');
const MONGO = require('mongodb').MongoClient;

router.get('/', middleWare(async (req, res, next) => {
    const db = await MONGO.connect(url);
    const MyCollection = db.collection('MyCollection');
    const result = await MyCollection.find(query).toArray();
    res.send(result);
}))

This is the smallest piece of code I found that is compatible with Mongo3 and async/await. Enjoy!

module.exports = {
  myFunction: async (query) => {
    let db, client;
    try {
      client = await MongoClient.connect(process.env.MONGODB_CONNECTION_STRING, { useNewUrlParser: true });
      db = client.db(dbName);
      return await db.collection(collectionName).find(query).toArray();
    } finally {
      client.close();
    }
  }
}

If u don't pass a callback, mongodb client returns a promise.

The official MongoDB Node.js driver provides both callback based as well as Promised based interaction with MongoDB allowing applications to take full advantage of the new features in ES6

From the official docs

Node.js mongodb driver async/await queries

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