Easy Mongo Collection access and management (promisified)

Usage no npm install needed!

<script type="module">
  import ezmc from 'https://cdn.skypack.dev/ezmc';


ezmc - Easy Mongo Collection access and management

This module abstracts common database operations to provide a minimal API for data management. Using the base mongodb drive one must go through a number of steps to perform a collection operation.

const MongoClient = require('mongodb').MongoClient;
const client = new MongoClient('connectionString');

const countPromise = client.connect('connectionString')
.then(() => client.db('dbName'))
.then(function (db) {
  const collection = db.collection('MyCollection');
  return collection.count():

// Perform action on count
countPromise.then(function (count) {
  console.log(`MyCollection has ${count} documents`));

Mongo suggest that we only have one MongoClient per application, so we are also responsible for keeping this one client around. ezmc solves all of these problems and provides one line invocation for all collection methods.

const Ezmc = require('ezmc');
const client = new Ezmc('connectionString', 'dbName')

  .then(function (count) {
    console.log(`MyCollection has ${count} documents`));


  • Node.js 4.4.x - 6.2.x

Install & use

First install ezmc

npm install --save ezmc

Secondly, to ensure there is only one instance for your entire application, we suggest that you create a file that exports an initialized ezmc. You then reference this file everywhere you want to use ezmc.

// mongoCollections.js
const Ezmc = require('ezmc');

module.exports = new Ezmc('connectionStrings', 'dbName', options);

You can then use the same instance anywhere in your application

// index.js
const mongoCollections = require('../path/to/mongoCollections');

return mongoCollections.count('MyCollection')
  .then(function (count) {
    console.log(`MyCollection has ${count} documents`);


We found ourselves writing the same lines of code over and over whenever we needed access to the collections. This introduced extra surface for errors and confusion. Secondly, it made testing a bit more difficult as we had to always stub out an extra layer or two just as setup. Finally, we did not have a consistent way of keeping one MongoClient around the entire application.

In order to keep things DRY we condensed our boilerplate code into one module. It's methods simply dereference the collection using it's single MongoClient and passes the arguments to the corrosponding Collection method.


Every methods first argument is the name of the collection you're referencing. The arguments following that will be passed directly to the Mongo collection. The Mongo Collection documentation (linked under each method here) will provided details on the parameters and return values. Every method returns a promise.

  • initializer (connectionString, options) Mongo Docs

  • close() Close the database connection Mongo Docs

Standard Behaviour

  • bulkWrite(collectionName, operations, options) Mongo Docs
  • count(collectionName, query, options) Mongo Docs
  • createIndex(collectionName, fieldOrSpecs, options) Mongo Docs
  • createIndexes(collectionName, indexSpecs) Mongo Docs
  • deleteMany(collectionName, filter, options) Mongo Docs
  • deleteOne(collectionName, filter, options) Mongo Docs
  • distinct(collectionName, key, query, options) Mongo Docs
  • drop(collectionName) Mongo Docs
  • dropIndex(collectionName, indexName, options) Mongo Docs
  • dropIndexes(collectionName) Mongo Docs
  • find(collectionName, query) Mongo Docs
  • findOneAndDelete(collectionName, filter, options) Mongo Docs
  • findOneAndReplace(collectionName, filter, replacement, options) Mongo Docs
  • findOneAndUpdate(collectionName, filter, update, options) Mongo Docs
  • geoHaystackSearch(collectionName, x, y, options) Mongo Docs
  • geoNear(collectionName, x, y, options) Mongo Docs
  • group(collectionName, keys, condition, initial, reduce, finalize, command, options) Mongo Docs
  • indexes(collectionName) Mongo Docs
  • indexExists(collectionName, indexes) Mongo Docs
  • indexInformation(collectionName, options) Mongo Docs
  • insertMany(collectionName, docs, options) Mongo Docs
  • insertOne(collectionName, doc, options) Mongo Docs
  • isCapped(collectionName) Mongo Docs
  • listIndexes(collectionName, options) Mongo Docs
  • mapReduce(collectionName, map, reduce, options) Mongo Docs
  • options(collectionName) Mongo Docs
  • parallelCollectoinScan(collectionName, options) Mongo Docs
  • reIndex(collectionName) Mongo Docs
  • rename(collectionName) Mongo Docs
  • replaceOne(collectionName, filter, doc, options) Mongo Docs
  • stats(collectionName) Mongo Docs
  • updateMany(collectionName, filter, update, options) Mongo Docs
  • updateOne(collectionName, filter, update, options) Mongo Docs

Non-standard Behaviour

  • aggregate(collection, pipeline, options) Mongo Docs Docs](http://mongodb.github.io/node-mongodb-native/2.0/api/Collection.html#aggregate)
  • Will return an array of results instead of a cursor unless options.returnCursor is true
  • find(collection, query, options) Mongo Docs
  • Will return an array of results instead of a cursor unless options.returnCursor is true
  • findOne(collection, query, options) Mongo Docs
  • Convience method. Simply calls find with the same arguments but adds options.limit = 1
  • Returns the document if it's found, and null if it is not. Does not return an array.