Let's pretend we have a real MongoDB

Usage no npm install needed!

<script type="module">
  import mongoMock from '';


mongo-mock     Build Status

This is an in-memory 'pretend' mongodb. The goal is to make the interface compatible with the real mongodb module so they are interchangeable.

There are a TON of features for mongo and I can't write them all myself- so pull requests are encouraged! My initial goal was to provide basic CRUD operations to enable this to work as a throw-something-together tool.


Maybe you don't want to (or can't) connect to a MongoDB instance for your tests?
Maybe you want to throw together a quick example app?

Demo code

var mongodb = require('mongo-mock');
mongodb.max_delay = 0;//you can choose to NOT pretend to be async (default is 400ms)
var MongoClient = mongodb.MongoClient;
MongoClient.persist="mongo.js";//persist the data to disk

// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, {}, function(err, client) {
  var db = client.db();
  // Get the documents collection
  var collection = db.collection('documents');
  // Insert some documents
  var docs = [ {a : 1}, {a : 2}, {a : 3}];
  collection.insertMany(docs, function(err, result) {

    collection.updateOne({ a : 2 }, { $set: { b : 1 } }, function(err, result) {

      collection.findOne({a:2}, {b:1}, function(err, doc) {
        console.log('foundOne', doc);

        collection.removeOne({ a : 3 }, function(err, result) {

          collection.find({}, {_id:-1}).toArray(function(err, docs) {
            function cleanup(){            
              var state = collection.toJSON();
              // Do whatever you want. It's just an Array of Objects.
              state.documents.push({a : 2});
              // truncate
              state.documents.length = 0;
              // closing connection
            setTimeout(cleanup, 1000);


Well, you know.. the usual:

$ npm install mongo-mock