Every question is easy to answer once you know the answer, the trick is finding the answer. It's often harder to know what you don't know, than actually finding the answer.

I agree with this statement, but in this case the author lists concrete things he has difficulty with, like => and promises.

I am responding based on my experience doing some react/redux work coming from a non-JS background, but the author says he is a designer so maybe that's where the difficulty is coming from.

That's not to say there aren't hard parts, but those come farther down the line when you're trying to do something unconventional.

I got the impression that he's spent a bit more than an afternoon.