I'd like to interject a question here. I'm not a front-end dev, but when I hear other front-end devs talk about stuff... several notables folks have talked about not chasing all the frameworks, because they're like fads, and you can get burned if $COMPANY or $TEAM stops maintaining them.
Is following the newest shiny framework really the best path to being a pro, or is it having a mastery of fundamentals?
That's a good point, the plethora of frameworks is actually a burden for front-end dev. Moreover the building process of moderns web-app is also a jungle (webpack, rollup, browserify, npm...).
Getting started as a front-end dev can easily lead to choice paralysis about framework as well as tutorial hell about building process.
On the other hand, mastering the fundamentals of JS isn't very fun in itself. It requires lot of dry reading with few practical examples, if you have few experience these examples are difficult to contextualize.
It may be more effective to pick one of the big three (Vue, Angular, React) and get your hands into it by building some fun stuff. Once you'll have practical knowledge, you'll have a better idea on what aspect of the fundamentals are worth digging.
Exposure to several different ones is ideal. Since most web UI frameworks are attempting to offer application functionality it is important to know at least one non-browser based (native) framework such as .NET, Swing, or Qt, even Motif would be good for an aspiring front-end dev.
Is following the newest shiny framework really the best path to being a pro, or is it having a mastery of fundamentals?