To me the question doesn't even make sense. Style is style, behavior is behavior, the two should not even meet -- and when they do that's what class triggers or direct manipulation of Element.style are for.
What you are asking about -- IF I understand the question -- is not even something I would be doing with CSS or JavaScript in the first place! Though just mentioning inline-styles or SCSS style mental huffing midgetry sets my teeth on edge.
In that way, how you worded it almost sounds like the type of thing that when I come across it in a codebase, I go "now what the blue blazes is this doing HERE?" -- but I do a lot more accessible website development than I do rinky slow broken web crapplets that tell users with accessibility needs to go perform anatomically impossible acts upon themselves.
Though if I'm misunderstanding it, could you give an example of what you mean?
-- edit -- following the links on github, I see that it's this type of cranial bleeding:
class="bold right green big italic"
If you're using classes that way, or assigning ANY of those types of values from your JS, you clearly do not know enough about HTML, CSS, or JavaScript to be working with web technologies; go back to that HTML 3.2 with all those deprecated presentational tags and attributes that everyone so clearly misses!
This is why I think that "frameworks" like react (and by extension "Material UI") are half-witted ignorant incompetent bullshit created for and by people who have no business writing a single line of HTML!
Garbage like this PROVES IT!!!
<div class="jss279 jss315 jss322 jss335 jss345 jss368 undefined">
<div class="jss84 jss88 jss85 jss369">
<div class="jss393 jss370 jss371">
<div class="jss394 jss378">
<svg class="jss251 jss377" focusable="false" viewBox="0 0 24 24" aria-hidden="true">
<g>
<path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"></path>
</g>
</svg>
</div>
<div class="jss396">
<span class="jss399 jss407 jss397"></span>
</div>
</div>
<div class="jss423 jss376">
<p class="jss399 jss408 jss379">Used Space</p>
<h2 class="jss399 jss404 jss380">
49/50
<small class="jss381">GB</small>
</h2>
</div>
<div class="jss424 jss382">
<div class="jss383 jss425">
<svg class="jss251 jss384 jss387" focusable="false" viewBox="0 0 24 24" aria-hidden="true">
<g>
<path d="M1 21h22L12 2 1 21zm12-3h-2v-2h2v2zm0-4h-2v-4h2v4z"></path>
</g>
</svg>
<a href="#pablo" class="jss392">Get More Space...</a>
</div>
</div>
</div>
</div>
A little semantics? Leveraging selectors? Any of this ring any bells? OH, what am I saying, of course not. That would involve actually learning how to use HTML and CSS before diving for the scripttardery.
There is NO excuse apart from complete ignorance and/or incompetence -- be it as vanilla markup or generated by JavaScript -- for that to be anything more than:
<div class="panel icon-used-space">
<h2>Used Space</h2>
49/50 <span>GB</span>
<a href="#" class="icon-warning">Get More Space...</a>
</div>
THAT"S how stupid garbage like react and material ui are. WHY THE BLAZES do people make so much work out of something so huffing simple?!?