Slagging the author for giving something to the world for free doesn't help anyone and it's almost certainly going to discourage the sharing which everyone on the internet has benefited from.
I feel like learning is always easier in smaller bitesizes and the person wrote something very clear and digestible. Sounds like it wasn't aimed at more advanced programmers like yourself
* Better understanding the topic by trying to re-teach it
* Improve writing skills. Programming is basically writing but with even crazier grammar freaks.
* Employers interested in possibly hiring you will have a better idea of what you know & enjoy
* Provide yourself (and possibly your company) with documentation for the future.
Lastly if you need encouragement by someone more established than me, here's Troy Hunt at NDC Oslo 2017 - https://www.youtube.com/watch?v=-MUhcgXBj_A
(It's unlikely it'll benefit arkadiytehgraet, but he probably finds that with a great many things.)
When I first started learning this stuff, I started a blog. I made maybe 3 posts before giving up on it, thinking about how much I didn't know, how that everything I could write about at the time was probably covered elsewhere and better, etc.
Several years later I regret giving up.
A lot of writing is writing for yourself. Obvious benefits to that, one of which is hopefully you get better at communication, which is huge in life in general, not just a career as a dev on a team.
Another is learning through teaching or keeping a record. I've probably forgotten a bunch of things over the years that, had I written them in my blog I may remember, or at least know where to find the post instead of scouring the internet looking for another post by someone else that I used to helped me solve a problem.
Potential employers may like seeing a blog as well. You can tell someone you're passionate about x, but where's the proof of that passion? It may not be the most in depth blog like Dr. Axel Rauschmeyer's, but it'll still show what you know. And you never know who's reading, so you may help someone in the process.
The internet is already filled with "litter" or useless things. But if you're getting use out of it then that's the main point to focus on.
If you think you have something valuable or interesting or just funny to share, that either was never discussed or written about or you know you can do better, then you absolutely should blog about it and do not let haters like me stop you.
As for the original article:
* It should have been named just "JavaScript arrays and higher-order functions" (I get that using term functional programming is very catchy nowadays, but I am trying to talk about quality here, not clickbaitness)
* As it is aimed for people unfamiliar with the concept and coming from more imperative background, where first-class functions are either not present or not that popular or handy to work with, an introduction (even the most gentle one) would be very suitable
* Then the introduction of filter/map/reduce functions would be in place, ideally compared in place with imperative implementation of the same task
* The best way to make sure a reader understands how each of this functions works is to make them implement each one of them, even the naive implementation would suffice
* Finally, you could provide some reasonably unobvious usages of any of the functions, e.g. insertion sort done with fold-only.
Sounds like you should be curating a list.
The article is not ground breaking or even front page worthy, but that doesn't mean it's the litter of the Internet. At absolute worst it's an exercise in thinking about a subject and trying to explain it to others.
When I first started reading Hacker News, I had never heard of functional programming...or Python.
This may not provide value to you and thats completely fine. This does however provide a lot of value to the author and to others.
Writing technical thoughts in a way that is simple and understandable is a skill and I think this author did a great job of that.
Also its the internet I can write posts for myself all day long and guess what? Ain't shit you can do about it. I'll keep littering the internet with these "random abrupt posts".
It's like someone showing you multiplication and saying. See look how useful it is! See look how simple and easy it is to understand! I still don't know multiplication, or even addition for that matter.
Map and reduce are things you build up to by doing recursive functions over and over again. They are not something you learn from reading an article. Just like you can't read an article and suddenly know how to solve problems with long division.
I have been wondering lately what is the value of articles like this. They do not convey any meaningful idea, they do not offer any useful insight on underlying matters; why do people even write something like this, except to litter the Internet even more? Anyone, who is distinctly familiar with functional programming or even just with the concept of higher order functions, surely knows those three basic primitives; those, who are not, would benefit much more from the basic concepts of first-class functions etc, than this random abrupt post.