Yahoo has just announced they will immediately stop all new development on Yahoo User Interface (YUI). Julien Lecomte, Director of Engineering at Yahoo Presentation, made this revelation in the Yahoo Engineering Tumblr blog and stated: "We have made the difficult decision to immediately stop all new development on YUI in order to focus our efforts on this new technology landscape".
According to Julien, the company took this decision based on the recent evolution of the JavaScript language and the decreasing interest in large libraries by developers. Most YUI core modules do not have active maintainers and relies on external contributors that have been slowly reducing.
The development of YUI started in 2005 by Thomas Sha and was sponsored by Yahoo co-founder Jerry Yang. The first public release was in February 2006 and since then a core team of Yahoo engineers has actively developed it. In September 2009, the latest major version of YUI (YUI3) was released. It represented a rebuilt from the ground up to contemporize the library and integrate lessons learned from YUI2. Among the enhancements were a CSS selector driven engine for retrieving DOM elements, a greater emphasis on granularity of modules, a smaller seed file that loads other modules when necessary, and a variety of syntactic changes intended to make writing code faster and easier.
YUI pioneered some techniques that are popular among JavaScript developers such as modules and dynamic loading which made modular development and dependency management easier. However, in the last years JavaScript gained another momentum in Web applications with Node.JS, as Julien said:
It has become clear to us that the industry is now headed in a new direction. As most of you know, the web platform has been undergoing a drastic transformation over the past few years. JavaScript is now more ubiquitous than ever. The emergence of Node.JS has allowed JavaScript to be used on the server side, opening the door to creating isomorphic single page applications.
The JavaScript ecosystem changed drastically with this new technology as Julien describes:
New package managers (npm, bower) have spurred the rise of an ecosystem of 3rd party, open source, single-purpose tools that complement each other, embracing the UNIX philosophy and enabling very complex development use cases. New build tools (Grunt and its ecosystem of plugins, Broccoli, Gulp) have made it easier to assemble those tiny modules into large, cohesive applications. New application frameworks (Backbone, React, Ember, Polymer, Angular, etc.) have helped architect web applications in a more scalable and maintainable way. New testing tools (Mocha, Casper, Karma, etc.) have lowered the barrier of entry to building a solid continuous delivery pipeline. Standard bodies (W3C, ECMA) are standardizing what the large JavaScript frameworks have brought to the table over the years, making them available natively to a larger number of devices. Finally, browser vendors are now committed to making continuous improvements to their web browsers while aligning more closely with standards. With so called “evergreen web browsers”, which are making it easier for users to run the latest stable version of a web browser, we can expect a significant reduction in the amount of variance across user agents.
Because of the agility around JavaScript, Julien states that:
The consequence of this evolution in web technologies is that large JavaScript libraries, such as YUI, have been receiving less attention from the community. Many developers today look at large JavaScript libraries as walled gardens they don’t want to be locked into.
Although Yahoo stopped new developments, critical bugs will still be addressed:
New YUI releases will likely be few and far between, and will only contain targeted fixes that are absolutely critical to Yahoo properties.