This is a very solid foundation to work with, for anyone who might have struggled with the contexts and how arrow functions, local variables, thises (hah) and prototypes fit into the bigger picture.
It also clearly shows that Javascript is not the mess that it looks like from a beginner's perspective. Yes, anyone can create a 15-20 min video about how == and === can mess up stuff, how you cant just pass around a function with a this in it without being careful, how NaN is wtf, and all that jazz. But at the end of the day, stick to this language long enough and it works for you.
It also clearly shows that Javascript is not the mess that it looks like from a beginner's perspective. Yes, anyone can create a 15-20 min video about how == and === can mess up stuff, how you cant just pass around a function with a this in it without being careful, how NaN is wtf, and all that jazz. But at the end of the day, stick to this language long enough and it works for you.