Treffer: An Evaluation of Reactive Programming and Promises for Structuring Collaborative Web Applications

JavaScript programs are highly event-driven, resulting in ‘asynchronous spaghetti ’ code that is difficult to maintain as the magnitude programs written in the language grows. To reduce the effects of this callback hell, various concepts have been employed by a number of JavaScript libraries and frameworks. In this paper we investigate the expressiveness of two such techniques, namely reactive extensions and promises. We have done this by means of a case study consisting of an online collaborative drawing editor. The editor supports advanced drawing features which we try to model using the aforementioned techniques. We then present a discussion on our overall experience in implementing the application using the two concepts. From this, we propose a roadmap of how to improve support of programming eventdriven web applications in JavaScript.