Yjs is a CRDT implementation. It implements an adaptation of the YATA CRDT with improved runtime performance.
(PDF) Near Real-Time Peer-to-Peer Shared Editing on Extensible Data Types
Choosing efficient data structures is critical when implementing a CRDT. The following document gives an overview of the data structures used in Yjs.
yjs/INTERNALS.md at main · yjs/yjs
Visualization of different CRDT algorithms (including Yjs/YATA and Automerge/RGA).