If you look at a snippet of code in a language you don’t understand you wouldn’t call it intuitive. Once you learn the language you might see that what what was unintuitive before is intuitive and idiomatic now.

Once you learn how RxJS works examples like the one anbove anre intuitive.

Angular 2’s most egregious crime is that their tutorials try to make it (and RxJS) seem “simple”. They aren’t. They’re powerful.