Citrea and swarm: partially ordered op logs in the browser: implementing a collaborative editor and an object sync library in JavaScript

Principles of eventual consistency are normally applied in large-scale distributed systems. I report experiences applying EC in Web app development. Citrea is a collaborative rich text editor employing the Causal Trees[4] technology of concurrency/version control (note: CT is not an OT flavor). CT employs symbol ids and trees and, generally, belongs to the same family as WOOT, Logoot or Treedoc [1--3]. CT makes the ids-and-trees approach production-practical by limiting itself to simple and lightweight algorithms and data structures. Swarm is a JavaScript object sync library that works in the browser, in real time. Swarm fully employs client-side storage and works well under intermittent connectivity. Swarm employs "pure" op-based model, although I find that state- vs op-based separation is rather bogus in practice. Our top finding is a specifier, a serialized event description format that enables straightforward operation storage, caching and exchange.