Yjs is a framework for optimistic concurrency control and automatic conflict resolution on arbitrary data types. The framework implements a new OT-like concurrency algorithm and provides similar functionality as ShareJs and OpenCoweb. Yjs was designed to take away the pain from concurrently editing complex data types like Text, Json, and XML. You can find some applications for this framework here.

In the future, we want to enable users to implement their own collaborative types. Currently we provide data types for

• Text
• Json
• XML

Unlike other frameworks, Yjs supports P2P message propagation and is not bound to a specific communication protocol. Therefore, Yjs is extremely scalable and can be used in a wide range of application scenarios.

We support several communication protocols as so called Connectors. You find a bunch of Connectors in the y-connectors repository. Currently supported communication protocols:

• XMPP-Connector - Propagates updates in a XMPP multi-user-chat room
• WebRTC-Connector - Propagate updates directly with WebRTC
• IWC-Connector - Inter-widget Communication

You can use Yjs client-, and server- side. You can get it as via npm, and bower. We even provide a polymer element for Yjs!

The theoretical advantages over similar frameworks are support for

• .. P2P message propagation and arbitrary communication protocols
• .. arbitrary complex data types
• .. offline editing: Only relevant changes are propagated on rejoin (unimplemented)
• .. AnyUndo: Undo any action that was executed in constant time (unimplemented)
• .. Intention Preservation: When working on Text, the intention of your changes are preserved. This is particularily important when working offline.

Use it!

You find a tutorial, examples, and documentation on the website.

Either clone this git repository, install it with bower, or install it with npm.

Bower

bower install rwth-acis/yjs

Then you include the libraries directly from the installation folder.

<script src="./bower_components/yjs/y.js"></script>

Npm

npm install yjs --save

And use it like this with npm:

Y = require("yjs");

Status

Yjs is still in an early development phase. Don't expect that everything is working fine. But I would become really motivated if you gave me some feedback :) (github).

Current Issues

• The History Buffer should be able to store operations in a database
• Documentation
• Reimplement support for XML as a data type
• Custom data types

Support

Please report any issues to the Github issue page! I would appreciate if developers give me feedback on how convenient the framework is, and if it is easy to use. Particularly the XML-support may not support every DOM-methods - if you encounter a method that does not cause any change on other peers, please state function name, and sample parameters. However, there are browser-specific features, that Y won't support.

License

Yjs is licensed under the MIT License.

kevin.jahns@rwth-aachen.de