chore(main): release 6.18.0

[github-actions]

🌱 A new release!

6.18.0 (2025-07-22)

The MongoDB Node.js team is pleased to announce version 6.18.0 of the mongodb package!

Release Notes

Cursors lazily instantiate sessions

In previous versions, sessions were eagerly allocated whenever a cursor was created, regardless of whether or not a cursor was actually iterated (and the session was actually needed). Some driver APIs (FindCursor.count(), AggregationCursor.explain() and FindCursor.explain()) don't actually iterate the cursor they are executed on. This can lead to client sessions being created and never being cleaned up.

With this update, sessions are not allocated until the cursor is iterated.

Idle connections are now pruned during periods of no activity even when minPoolSize=0

A MongoClient configured with a maxIdleTimeMS and minPoolSize of 0 is advantageous for workloads that have sustained periods of little or no activity because it allows the connection pool to close connections that are unused during these periods of inactivity. However, due to a bug in the ConnectionPool implementation, idle / perished connections were not cleaned up unless minPoolSize was non-zero.

With the changes in this PR, the ConnectionPool now always cleans up idle connections, regardless of minPoolSize.

CommandSucceededEvent and CommandFailedEvent events now have a databaseName property

CommandSucceededEvent and CommandFailedEvent now include the name of the database against which the command was executed.

Transaction state getters are deprecated

These were for internal use only and include:

Transaction#options
Transaction#recoveryToken
Transaction#isPinned
Transaction#isStarting
Transaction#isActive
Transaction#isCommitted

ClientMetadata, ClientMetadataOptions, and CancellationToken have been deprecated.

These types will be removed in an upcoming major version of the driver.

New appendMetadata API allows clients to add handshake metadata post construction

Driver information such as name, version, and platform are allowed:

import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGODB_URI);
client.appendMetadata({ name: 'my library', version: '1.0', platform: 'NodeJS' });

CommandOptions.noResponse is deprecated

Caution

noResponse is not intended for use outside of MongoClient.close(). Do not use this option.

The Node driver has historically supported an option, noResponse, that is used internally when a MongoClient is closed. This option was accidentally public. This option will be removed in an upcoming major release.

ChangeStream event interfaces include a wallTime property

This property is available on all types with the exception of reshard collection and refine collection shard key events. Thanks to @qhello for bringing this bug to our attention!

Features

• NODE-5055: Add databaseName property to command monitoring events (#4586) (3faf0c9)
• NODE-6865: deprecate transaction getters (#4567) (da46aea)
• NODE-6991: deprecate unintentionally public client metadata types (#4566) (ca6554b)
• NODE-7009: add client metadata on demand (#4574) (b9636ee)
• NODE-7053: deprecate noResponse option (#4589) (1115319)

Bug Fixes

• NODE-4845: allocate sessions lazily in cursors (#4575) (5761703)
• NODE-6589: background task does not prune idle connections when minPoolSize=0 (#4569) (7cbb641)
• NODE-6955: add missing wallTime property TS change stream event interfaces (#4541) (f153c6f)

Documentation

• Reference
• API
• Changelog

We invite you to try the mongodb library immediately, and report any issues to the NODE project.

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[github-actions]

🤖 Created releases:

• v6.18.0

🌻