Well in that case I wouldn't name the variable as "n". It doesn't mean anything and decreases the readability.

"f" would be cool, or better: "friend".

Fixed

Approved

"Input strings will only contain letters."

How about the name with number ?

Great solution, thank you. I overcomplicated myself using .split("") and a condition but this is smart. Gotta remember about filter.

Names with numbers will be a trend .. apparently

Description says "a name has exactly 4 letters in it". Not numbers.

I only dislike "n" as a name. "N" doesn't say anything about what we are dealing with. It should be friendName or friend imo.

the most ingenious solution!!

This soulution passed only basic test? bcs string from 4 numbers like '3333' is not a name)

Because the author doesn't mention it and everyone is lazy pretty much

In any case, the code above can give a name consisting of 4 digits.

Numbers in the basic tests:
assert.deepEqual(friend(["Ryan", "Jimmy", "123", "4", "Cool Man"]), ["Ryan"])