Building Collaborative Apps: JavaScript Operational Transform

We should never have to refresh a page or look at stale data. We need our apps to be realtime, always updating, even when we’re not using them. Apps should be collaborative, and operational transform is the way to do that.

In his talk below from SF JavaScript at PubNub HQ, Joseph Gentle walks through how operation transform works, how to build apps using this technology (with in this case ShareJS and DerbyJS), and what tools we really want that nobody has built yet.

Joseph worked on Google Wave in Sydney, and his heart was broken when it was cancelled. Since all problems can be solved with code, he’s spent the last 3 years rebuilding a lot of Wave’s unique technology as an open source library. The end result is ShareJS, an open source operational transform library for NodeJS and browsers.

Building Collaborative Apps: JavaScript Operational Transform from PubNub on Vimeo.

Operational Transform Overview

Operational Transform (OT) is a technology that enables developers to build collaborative applications. When you think of an OT use case, think collaborative editors: Google Docs, Mockingbird, Zoho Suite, etc. Users can collaborate in an environment and their changes are reflected in realtime across all devices connected.

There are 3 benefits to using operational transform:

1. Your model data gets updated in realtime
2. Seamless online/offline integration
3. We never accidentally over write our data (F/LWW)

The best kept secret of Google Wave and hackpad is that operational transform (the collaboration algorithms) can be used to edit almost any JSON data. As a result, you can add realtime collaborative features to anything! And you can do it in a way that never loses user data and never needs to lock or add messy conflict markers.