Javascript – Node.js mongodb driver async/await queries

async-awaitjavascriptmongodbmongoosenode.js

I have a node.js application using mongodb native driver.
In the process of migrating my application code to async/await using node v8.9.1, I am struggling to find an elegant way for the mongodb queries.
The major problem with mongodb driver is, that all queries are using callbacks where promises functions are mandatory for the async methods.

Alternatives:

  • mongoose– promises queries deprecated and it forces using Schema model which is a little overhead for my app.
  • mongoist– allegedly great, since it built with async/await in mind and fully promise, but errors with SSL connection to mongodb and poor documentations- drew me away from this solution.

The only workaround I succeeded to implement in an elegant way is using callback-promise npm package to convert mongodb driver API to fully promise.

Any fresh ideas for an elegant high performance way?

Best Answer

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();
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