Suggested anonymously via sticky note at the meetup.
Here is a link to the EventStore.js library: http://eventstore.js.org/
This is what event sourcing is, and seems to be what the above library sets out to do: https://martinfowler.com/eaaDev/EventSourcing.html
And this is what CQRS is: https://www.martinfowler.com/bliki/CQRS.html