I find the opposite to be true. I believe nested ternary to be very readable. It really comes down to a matter of familiarity and ends up in a format similar to a switch or ramda's cond. I actually prefer ramda's cond is most situations.
These techniques themselves are not functional techniques. They are to provide alternatives to the traditional imperative code, but it is neither imperative or functional.
But since an if statement is anti-functional, learning alternatives to the if statement will help you when creating functional code.
Focusing in on this single article, it may not make as much sense, but when given the context of the larger body of articles I am writing, this technique becomes important.
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