The video is up for a talk I gave at QCon 2014 in which I spoke about the benefits of using immutable data to build a frontend and my experience working on Prismatic’s ClojureScript web application.
Brief summary: Mutable state is ubiquitous in UI programming and contributes to large amounts of additional complexity and bugs. Functional reactive data-flows can greatly simplify rendering logic and state management. ClojureScript’s immutable data structures pair nicely with React.js to build UIs that are declarative and performant.