CRDT framework with a powerful abstraction of shared data

 Yjs is a conflict-free replicated data type (CRDT) implementation
 that exposes its internal data structure as shared types. Shared
 types are common data types like Map or Array with superpowers:
 changes are automatically distributed to other peers and merged
 without merge conflicts.
 .
 Yjs is network agnostic (p2p!), supports many existing rich text
 editors, offline editing, version snapshots, undo/redo and shared
 cursors. It scales well with an unlimited number of users and is well
 suited for even large documents.
 .
 Node.js is an event-based server-side JavaScript engine.