test.es6

"use strict";

let async = require("async");
let MongoClient = require('mongodb').MongoClient;

MongoClient.connect('mongodb://127.0.0.1:27017/fhir', function(err, db) {
  let patientCollection = db.collection('patients');
  let cursor = patientCollection.find()
  async.waterfall([
    callback => {
      cursor.toArray(function(err, items) {
        callback(err, items);
      });
    },
    (items, callback) => {
      console.log("count: " + items.length);
      callback(null);
    }
  ], () => db.close());
});