[nine_k]

If a framework goes away because a clearly better alternative crops up, it is called progress :-)

In 2006, YUI was a step forward compared to the general state of JS frameworks. Today ReactJS is a step forward compared to YUI. When something supplants ReactJS because it's clearly better, I hope, nostalgia aside, few people will protest.

[IgorPartola]

I will bet $5 that you never had the experience where you build on top of a platform or learn to rely on a product and suddenly it gets taken out to pasture. Nostalgia is one thing, but realizing that the application that you are supposed to support and develop for years to come is built on a platform that no longer exists really sucks. It sucks in very real, very pragmatic terms, and for all the progress we can make in the general sense, the specific case of it happening to you is not going to be much easier just because there are now better alternatives and you have an excuse to start from scratch.

[nawitus]

One way to reduce this risk is modularization. If development stops for a single module, it can be replaced quite painlessly compared to rewriting everything because one relied on a monolithic framework.

[IgorPartola]

Yes. The problem is that things like YUI (or Django, or NodeJS, or Rails) are not modules. These are frameworks where you plug your code in, not the other way around. And besides, the dictate the programming paradigm, not just variable names. You cannot create an abstraction layer on top of YUI that would work seamlessly for Angular or jQuery or straight DOM manipulation. They are completely different.

[s1implr]

I agree that YUI can be seen like this, with its relatively deep object relationships and manipulations required for its mvc, widgets, etc. -- but does not have to be used as such. I've been using YUI the last couple of years in a lighter way. My code uses as much modern JS as practical, and dips in to YUI for things that are tedious to do by hand. Most of my modules can be swapped out to work with requirejs, jquery, underscore, handlebars, etc. without too much fuss. I've done that a few times when YUI was slowing down and showing signs of neglect, but then went back to YUI because I saw no noticeable signs of improvement, but rather found the code more difficult to maintain -- multiple dependencies vs. 1, and each of those libraries has a multiplicative effect (different documentation locations and styles, following the updates, engaging the community, finding workarounds, etc.) For a long time YUI had great docs, great participation from core devs, and a nurturing attitude towards 3rd party modules. It is when that love began to fade, without explanation -- the promises of improvements in the future began to gather cobwebs, and the community infrastructure began to crumble (forum, gallery, web site), yui dev participation plummeted -- that I and I'm sure many other YUI users began to disengage with the YUI project, even if we were still using it.

[nawitus]

What I mean is that YUI is a large, monolithic framework, which can be replaced with a number of smaller libraries/frameworks. This is modularization, which reduces the risk of a large monolithic framework losing maintenance support.

[Sivart13]

Calling ReactJS a step forward from YUI is an extremely applesy/orangey comparison. YUI was a full-fledged do-everything framework, React is more like a hyper-efficient templating language.