It is. But the hardest thing about the user is interacting with them. When the user does something, something in the program changes, and you have to change the screen to match. Or updating the screen when some information comes in from outside (like an API call).
That's basically what the article is about: keeping state in synch with the user interface. There are a bunch of different ways to do it. TFA compares a few of them.
A front end has to do a lot of other things, and it's kinda overstating it to say that state is "the single most important factor". But maybe not by much.
That's basically what the article is about: keeping state in synch with the user interface. There are a bunch of different ways to do it. TFA compares a few of them.
A front end has to do a lot of other things, and it's kinda overstating it to say that state is "the single most important factor". But maybe not by much.