I'm sorry to say that I completely agree. As a "here's how you do X in javascript" this is a great post. However, the conclusion clearly shows that this post was not aimed at people who already know how to use map and reduce: "Functional programming is a great tool and will drastically improve your productivity...."
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.
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.