Please do not post comments with code or solutions without the spoiler flag, otherwise anyone can see them.

I have added the flag to your comment.

im guessing people just blindly click the upvotes just because its at the top

him: making the solution longer by adding turnary operator
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26 people: C L E V E R

Good point

Why add the trinary operator, opposed to just returning the expression in the parentheses?

Awesome!

Fixed.

If the input array is empty or null, return an empty array.

Pretty sure null has no length property. ;)

The right error message you should be seeing is this:

TypeError: Cannot read property 'length' of null

The expected solution is not clear.
Yes it works if the array is empty or null.
But [0,0] is neither empty or null. It has two elements 0 and 0.
So this needs to be fixed.

Why not? The sooner the better (and after all, writing sample tests for this kata is easy), but the sample tests were located in the real tests tab, so I moved them and added random tests there.

Ok see your point if it is a higher level kata.
But an 8kyu is expected to write their own test?

// TODO: Replace examples and use TDD development by writing your own tests

You have to write your own tests there, that's just a template.