To be fair to good JS backend devs, my view is biased by the fact that me and my team do Python and Golang work and the only time we interact with JS devs is when there is frontend to be written. Some frontend guys are good, most of them are poorly trained and those think they can write backend code and lobby managers to let them have a go at it. With disastrous results. I have never worked with JS backend devs who were any good. I am sure they exist, but I have yet to meet one.
