mongodb

What is mongodb?

The mongodb npm package is the official Node.js driver for MongoDB. It provides a high-level API to connect to and interact with MongoDB databases. With this package, developers can perform CRUD operations, manage database connections, and work with MongoDB features like transactions, indexes, and aggregation.

What are mongodb's main functionalities?

Connecting to a MongoDB database

This code sample demonstrates how to connect to a MongoDB database using the MongoClient object provided by the mongodb package.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
async function connect() {
  try {
    await client.connect();
    console.log('Connected to MongoDB');
  } catch (e) {
    console.error(e);
  }
}
connect();

CRUD Operations

This code sample shows how to perform CRUD (Create, Read, Update, Delete) operations on a MongoDB collection using the mongodb package.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
const dbName = 'myDatabase';
async function crudOperations() {
  try {
    await client.connect();
    const db = client.db(dbName);
    const collection = db.collection('documents');

    // Create a document
    await collection.insertOne({ a: 1 });

    // Read documents
    const docs = await collection.find({}).toArray();

    // Update a document
    await collection.updateOne({ a: 1 }, { $set: { b: 1 } });

    // Delete a document
    await collection.deleteOne({ b: 1 });
  } catch (e) {
    console.error(e);
  } finally {
    await client.close();
  }
}
crudOperations();

Index Management

This code sample illustrates how to manage indexes in a MongoDB collection, including creating an index and listing all indexes.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
const dbName = 'myDatabase';
async function manageIndexes() {
  try {
    await client.connect();
    const db = client.db(dbName);
    const collection = db.collection('documents');

    // Create an index
    await collection.createIndex({ a: 1 });

    // List indexes
    const indexes = await collection.indexes();
    console.log(indexes);
  } catch (e) {
    console.error(e);
  } finally {
    await client.close();
  }
}
manageIndexes();

Aggregation

This code sample demonstrates how to use the aggregation framework provided by MongoDB to process data and compute aggregated results.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
const dbName = 'myDatabase';
async function aggregateData() {
  try {
    await client.connect();
    const db = client.db(dbName);
    const collection = db.collection('documents');

    // Perform an aggregation query
    const aggregation = await collection.aggregate([
      { $match: { a: 1 } },
      { $group: { _id: '$b', total: { $sum: 1 } } }
    ]).toArray();
    console.log(aggregation);
  } catch (e) {
    console.error(e);
  } finally {
    await client.close();
  }
}
aggregateData();

Other packages similar to mongodb

mongoose

Mongoose is an Object Data Modeling (ODM) library for MongoDB and Node.js. It manages relationships between data, provides schema validation, and is used to translate between objects in code and the representation of those objects in MongoDB. Mongoose offers a more structured approach to data handling with predefined schemas compared to the flexibility of the mongodb package.

couchbase

Couchbase is the official Node.js client library for the Couchbase database. While Couchbase is a different NoSQL database system with its own set of features and capabilities, the couchbase npm package offers similar functionalities in terms of CRUD operations, connection management, and querying as the mongodb package does for MongoDB.

redis

Redis is an in-memory data structure store, used as a database, cache, and message broker. The npm package for Redis provides Node.js bindings to the Redis server. It is similar to mongodb in that it allows for data storage and retrieval, but it operates in-memory and is typically used for different use cases such as caching.

README

MongoDB NodeJS Driver

The official MongoDB driver for Node.js.

Upgrading to version 4? Take a look at our upgrade guide here!

Quick Links

what	where
documentation	docs.mongodb.com/drivers/node
api-doc	mongodb.github.io/node-mongodb-native/4.2/
npm package	www.npmjs.com/package/mongodb
source	github.com/mongodb/node-mongodb-native
mongodb	www.mongodb.com
changelog	HISTORY.md
upgrade to v4	docs/CHANGES_4.0.0.md
contributing	CONTRIBUTING.md

Bugs / Feature Requests

Think you’ve found a bug? Want to see a new feature in node-mongodb-native? Please open a case in our issue management tool, JIRA:

• Create an account and login jira.mongodb.org.
• Navigate to the NODE project jira.mongodb.org/browse/NODE.
• Click Create Issue - Please provide as much information as possible about the issue type and how to reproduce it.

Bug reports in JIRA for all driver projects (i.e. NODE, PYTHON, CSHARP, JAVA) and the Core Server (i.e. SERVER) project are public.

Support / Feedback

For issues with, questions about, or feedback for the Node.js driver, please look into our support channels. Please do not email any of the driver developers directly with issues or questions - you're more likely to get an answer on the MongoDB Community Forums.

Change Log

Change history can be found in HISTORY.md.

Compatibility

For version compatibility matrices, please refer to the following links:

• MongoDB
• NodeJS

Typescript Version

We recommend using the latest version of typescript, however we do provide a downleveled version of the type definitions that we test compiling against typescript@4.0.2. Since typescript does not restrict breaking changes to major versions we consider this support best effort. If you run into any unexpected compiler failures please let us know and we will do our best to correct it.

Installation

The recommended way to get started using the Node.js 4.x driver is by using the npm (Node Package Manager) to install the dependency in your project.

After you've created your own project using npm init, you can run:

npm install mongodb
# or ...
yarn add mongodb

This will download the MongoDB driver and add a dependency entry in your package.json file.

If you are a Typescript user, you will need the Node.js type definitions to use the driver's definitions:

npm install -D @types/node

Troubleshooting

The MongoDB driver depends on several other packages. These are:

• bson
• bson-ext
• kerberos
• mongodb-client-encryption

Some of these packages include native C++ extensions. Consult the trouble shooting guide here if you run into issues.

Quick Start

This guide will show you how to set up a simple application using Node.js and MongoDB. Its scope is only how to set up the driver and perform the simple CRUD operations. For more in-depth coverage, see the official documentation.

Create the package.json file

First, create a directory where your application will live.

mkdir myProject
cd myProject

Enter the following command and answer the questions to create the initial structure for your new project:

npm init -y

Next, install the driver as a dependency.

npm install mongodb

Start a MongoDB Server

For complete MongoDB installation instructions, see the manual.

1. Download the right MongoDB version from MongoDB
2. Create a database directory (in this case under /data).
3. Install and start a mongod process.

mongod --dbpath=/data

You should see the mongod process start up and print some status information.

Connect to MongoDB

Create a new app.js file and add the following code to try out some basic CRUD operations using the MongoDB driver.

Add code to connect to the server and the database myProject:

NOTE: All the examples below use async/await syntax.

However, all async API calls support an optional callback as the final argument, if a callback is provided a Promise will not be returned.

const { MongoClient } = require('mongodb');
// or as an es module:
// import { MongoClient } from 'mongodb'

// Connection URL
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);

// Database Name
const dbName = 'myProject';

async function main() {
  // Use connect method to connect to the server
  await client.connect();
  console.log('Connected successfully to server');
  const db = client.db(dbName);
  const collection = db.collection('documents');

  // the following code examples can be pasted here...

  return 'done.';
}

main()
  .then(console.log)
  .catch(console.error)
  .finally(() => client.close());

Run your app from the command line with:

node app.js

The application should print Connected successfully to server to the console.

Insert a Document

Add to app.js the following function which uses the insertMany method to add three documents to the documents collection.

const insertResult = await collection.insertMany([{ a: 1 }, { a: 2 }, { a: 3 }]);
console.log('Inserted documents =>', insertResult);

The insertMany command returns an object with information about the insert operations.

Find All Documents

Add a query that returns all the documents.

const findResult = await collection.find({}).toArray();
console.log('Found documents =>', findResult);

This query returns all the documents in the documents collection. If you add this below the insertMany example you'll see the document's you've inserted.

Find Documents with a Query Filter

Add a query filter to find only documents which meet the query criteria.

const filteredDocs = await collection.find({ a: 3 }).toArray();
console.log('Found documents filtered by { a: 3 } =>', filteredDocs);

Only the documents which match 'a' : 3 should be returned.

Update a document

The following operation updates a document in the documents collection.

const updateResult = await collection.updateOne({ a: 3 }, { $set: { b: 1 } });
console.log('Updated documents =>', updateResult);

The method updates the first document where the field a is equal to 3 by adding a new field b to the document set to 1. updateResult contains information about whether there was a matching document to update or not.

Remove a document

Remove the document where the field a is equal to 3.

const deleteResult = await collection.deleteMany({ a: 3 });
console.log('Deleted documents =>', deleteResult);

Index a Collection

Indexes can improve your application's performance. The following function creates an index on the a field in the documents collection.

const indexName = await collection.createIndex({ a: 1 });
console.log('index name =', indexName);

For more detailed information, see the indexing strategies page.

Error Handling

If you need to filter certain errors from our driver we have a helpful tree of errors described in docs/errors.md.

It is our recommendation to use instanceof checks on errors and to avoid relying on parsing error.message and error.name strings in your code. We guarantee instanceof checks will pass according to semver guidelines, but errors may be sub-classed or their messages may change at any time, even patch releases, as we see fit to increase the helpfulness of the errors.

Any new errors we add to the driver will directly extend an existing error class and no existing error will be moved to a different parent class outside of a major release. This means instanceof will always be able to accurately capture the errors that our driver throws (or returns in a callback).

const client = new MongoClient(url);
await client.connect();
const collection = client.db().collection('collection');

try {
  await collection.insertOne({ _id: 1 });
  await collection.insertOne({ _id: 1 }); // duplicate key error
} catch (error) {
  if (error instanceof MongoServerError) {
    console.log(`Error worth logging: ${error}`); // special case for some reason
  }
  throw error; // still want to crash
}

Next Steps

• MongoDB Documentation
• MongoDB Node Driver Documentation
• Read about Schemas
• Star us on GitHub

License

Apache 2.0

© 2009-2012 Christian Amor Kvalheim © 2012-present MongoDB Contributors

Changelog

4.2.2 (2021-12-13)

Bug Fixes

• NODE-3705: ReadPreference.fromOptions omitting hedge and maxStalenessSeconds when readPreference is a string (#3060) (b9fbac5)
• NODE-3711: retry txn end on retryable write (#3045) (7b00d0f)
• NODE-3765: make replacement for replaceOne operations without _id (#3040) (e07e564)
• stricter protocol check in connection string (#3078) (bc05671)