Now is a good time to learn front-end tech. Skipping YUI was good, but you should learn at least one of Mithril, React, Preact, Inferno. I recommend Mithril for learning and React for job opportunities.
It's OK to have skipped CoffeeScript, but you don't want to skip TypeScript in 2018. The past couple of years have been good as it has increasingly harmonized with ES6.
