Proposal for https://github.com/jdesboeufs/connect-mongo/issues/472

[CarlosLunaGit]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Based on #472 we wonder; how to add createdAt and updatedAt timestamps to the MongoDB documents for better tracking and auditing?

• What is the current behavior? (You can also link to an open issue here)

createdAt and updatedAt do not exist, current data schema:
type InternalSessionType = {
_id: string
session: any
expires?: Date
lastModified?: Date
}

• What is the new behavior (if this is a feature change)?

createdAt and updatedAt exist and are pushed to the MongoDB under the following schema:
type InternalSessionType = {
_id: string
session: any
expires?: Date
lastModified?: Date
createdAt?: Date
updatedAt?: Date
}

• Other information:

The main code changes are in the set method of the MongoStore class. This method is responsible for both creating and updating sessions. The createdAt field is initialized when a new document is created, and the updatedAt field is updated whenever an existing document is updated.

• Checklist:

• [] Added test cases

• [] Updated changelog

[CarlosLunaGit]

Hello Team, please review and let me know your thoughts on this.

[ilias-t]

Thanks for this! No comment on the implementation, but from a usability perspective I'd also suggest having this be configurable via a parameter in the initialization object, for example something like { timestamps: true }. The default value could be false so that this change is purely opt-in.