and what is the understanding of native JS?
I, too, fought, thought, where I climb, yet as pure js does not understand! But no. Writing calculators and parallaxes (read: any other alterations) does not give almost anything, if only to get used to the syntax. If the person ultimately wants to do the frontend, and located immediately in the front-end makes sense. Still it has its own ecosystem, terminology and mechanisms. Still have to learn from scratch, whatever knowledge was not behind.
Again, in my experience, this approach proved more effective. I clung to the first framework, with pain studied him, lapping on the walls, spent a lot of nerves, but now I have and knowledge of this framework, and npm, and express, pug, Sass, axios - heap related effort, in other words. And if I still wrote on native js, trying to understand his fundamental truths? Obviously, now I also had to choose a framework, learn it with the same pain and without knowledge of js. The advantage of my approach is that the result is tangible immediately - it motivates me to move on.
Of course, I envy those who can write anything in pure js, but personally, my goal was to develop applications as possible rather than fight for the title of best speller.
I even thought that for this type of people, like me, better fit the term "developer" - they say, I do not know how to program, but collect the pieces of the working system can. And to correct her on a course of action. And there are programmers who know the language by heart, and to this endeavour, but I want to see the result, not know all the terms and intricacies. It still will come with time.
Excuse me, what signed, sleepless night)