Connecting

The MongoClient connection method returns a Promise if no callback is passed to it. Below is an example using the async/await commands.

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

(async function() {
  // Connection URL
  const url = 'mongodb://localhost:27017/myproject';
  // Database Name
  const dbName = 'myproject';
  let client;

  try {
    // Use connect method to connect to the Server
    client = await MongoClient.connect(url);

    const db = client.db(dbName);
  } catch (err) {
    console.log(err.stack);
  }

  if (client) {
    client.close();
  }
})();

The MongoClient.connect function returns a Promise that we then execute using the await keyword inside of an async function. If an error happens during the MongoClient.connect the error is caught by the try/catch and can be handled as if it were a normal Javascript error.