Caching values is an obvious and necessary optimization. The claim that the CSS transition cannot know when the property changes due to JS, therefore cannot op

Caching values is an obvious and necessary optimization. The claim that the CSS transition cannot know when the property changes due to JS, therefore cannot optimize, is total fluffery. The main loop is render, JS, and never at the same time. That is why a JS loop will freeze the browser. Have you no idea that it's all single threaded?